SEBM036406
© 2005
All Rights Reserved
Printed in Japan 01-05(03)
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CONTENTS
01 GENERAL
No. of page
................................................................................................................................. 01-1
10 DENSO (Freon Gas Type)
11
STRUCTURE AND FUNCTION........................................................................................... 11-1
12
TESTING AND ADJUSTING................................................................................................ 12-1
13
DISASSEMBLY AND ASSEMBLY ....................................................................................... 13-1
20 ZEXEL (DIESEL KIKl)
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STRUCTURE AND FUNCTION........................................................................................... 21-1
22
TESTING AND ADJUSTING................................................................................................ 22-1
23
DISASSEMBLY AND ASSEMBLY ....................................................................................... 23-1
30 DAIKIN
31
STRUCTURE AND FUNCTION........................................................................................... 31-1
32
TESTING AND ADJUSTING................................................................................................ 32-1
33
DISASSEMBLY AND ASSEMBLY ....................................................................................... 33-1
40 DENSO (New Refrigerant Type)
41
STRUCTURE AND FUNCTION........................................................................................... 41-1
42
TESTING AND ADJUSTING................................................................................................ 42-1
50 TAKAHASHI WORKS
51
STRUCTURE AND FUNCTION........................................................................................... 51-1
52
TESTING AND ADJUSTING................................................................................................ 52-1
60 SANDEN
61
STRUCTURE AND FUNCTION........................................................................................... 61-1
62
TESTING AND ADJUSTING................................................................................................ 62-1
63
DISASSEMBLY AND ASSEMBLY ....................................................................................... 63-1
70 ZEXEL VALEO (NEW REFRIGERANT (R134a) TYPE)
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STRUCTURE AND FUNCTION........................................................................................... 71-1
72
TESTING AND ADJUSTING................................................................................................ 72-1
73
TROUBLESHOOTING ......................................................................................................... 73-1
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<Reference>
DENSO : Denso Corporation
Corporate name has Changed
From Nippon Denso to Denso Corporation in 1996.
ZEXEL : Zexel Valeo Climate Control Corporation
Corporate name has Changed
From Diesel Kiki to Zexel in 1990, and
From Zexel to Zexel Valeo Climate Control Corporation in 2001.
DAIKIN : Daikin Industries, Ltd.
Corporate name has changed
From Daikin Kogyo to Daikin Industries, Ltd. in1982.
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Air conditioner
SAFETY
SAFETY NOTICE
SAFETY
SAFETY NOTICE
IMPORTANT SAFETY NOTICE
Proper service and repair is extremely important for safe machine operation. The service and
repair techniques recommended by Komatsu and described in this manual are both effective
and safe. Some of these techniques require the use of tools specially designed by Komatsu for
the specific purpose.
To prevent injury to workers, the symbol k is used to mark safety precautions in this manual.
The cautions accompanying these symbols should always be followed carefully. If any dangerous situation arises or may possibly arise, first consider safety, and take the necessary actions
to deal with the situation.
GENERAL PRECAUTIONS
Mistakes in operation are extremely dangerous.
Read the Operation and Maintenance Manual carefully BEFORE operating the machine.
1. Before carrying out any greasing or repairs, read
all the precautions given on the decals which are
fixed to the machine.
2. When carrying out any operation, always
wear safety shoes and helmet. Do not wear
loose work clothes, or clothes with buttons
missing.
•
•
Always wear safety glasses when hitting
parts with a hammer.
Always wear safety glasses when grinding
parts with a grinder, etc.
3. If welding repairs are needed, always have a
trained, experienced welder carry out the work.
When carrying out welding work, always wear
welding gloves, apron, hand shield, cap and
other clothes suited for welding work.
4. When carrying out any operation with two or
more workers, always agree on the operating
procedure before starting. Always inform your
fellow workers before starting any step of the
operation. Before starting work, hang UNDER
REPAIR signs on the controls in the operator's
compartment.
5. Keep all tools in good condition and learn the
correct way to use them.
6. Decide a place in the repair workshop to keep
tools and removed parts. Always keep the tools
and parts in their correct places. Always keep
the work area clean and make sure that there is
no dirt or oil on the floor. Smoke only in the areas
provided for smoking. Never smoke while working.
PREPARATIONS FOR WORK
7. Before adding oil or making any repairs, park the
machine on hard, level ground, and block the
wheels or tracks to prevent the machine from
moving.
8. Before starting work, lower blade, ripper, bucket
or any other work equipment to the ground. If
this is not possible, insert the safety pin or use
blocks to prevent the work equipment from falling. In addition, be sure to lock all the control
levers and hang warning signs on them.
9. When disassembling or assembling, support the
machine with blocks, jacks or stands before
starting work.
10.Remove all mud and oil from the steps or other
places used to get on and off the machine.
Always use the handrails, ladders or steps when
getting on or off the machine. Never jump on or
off the machine. If it is impossible to use the
handrails, ladders or steps, use a stand to provide safe footing.
00-3
SAFETY
PRECAUTIONS DURING WORK
11. When removing the oil filler cap, drain plug or
hydraulic pressure measuring plugs, loosen
them slowly to prevent the oil from spurting out.
Before disconnecting or removing components
of the oil, water or air circuits, first remove the
pressure completely from the circuit.
12.The water and oil in the circuits are hot when the
engine is stopped, so be careful not to get
burned.
Wait for the oil and water to cool before carrying out any work on the oil or water circuits.
13.Before starting work, remove the leads from the
battery. Always remove the lead from the negative (–) terminal first.
14.When raising heavy components, use a hoist or
crane.
Check that the wire rope, chains and hooks are
free from damage.
Always use lifting equipment which has ample
capacity.
Install the lifting equipment at the correct places.
Use a hoist or crane and operate slowly to prevent the component from hitting any other part.
Do not work with any part still raised by the hoist
or crane.
15.When removing covers which are under internal
pressure or under pressure from a spring,
always leave two bolts in position on opposite
sides. Slowly release the pressure, then slowly
loosen the bolts to remove.
16.When removing components, be careful not to
break or damage the wiring. Damaged wiring
may cause electrical fires.
17.When removing piping, stop the fuel or oil from
spilling out. If any fuel or oil drips onto the floor,
wipe it up immediately. Fuel or oil on the floor
can cause you to slip, or can even start fires.
18.As a general rule, do not use gasoline to wash
parts. In particular, use only the minimum of
gasoline when washing electrical parts.
00-4
SAFETY NOTICE
19.Be sure to assemble all parts again in their original places.
Replace any damaged parts with new parts.
• When installing hoses and wires, be sure
that they will not be damaged by contact
with other parts when the machine is being
operated.
20.When installing high pressure hoses, make sure
that they are not twisted. Damaged tubes are
dangerous, so be extremely careful when installing tubes for high pressure circuits. Also, check
that connecting parts are correctly installed.
21.When assembling or installing parts, always use
the specified tightening torques. When installing
protective parts such as guards, or parts which
vibrate violently or rotate at high speed, be particularly careful to check that they are installed
correctly.
22.When aligning two holes, never insert your fingers or hand. Be careful not to get your fingers
caught in a hole.
23.When measuring hydraulic pressure, check that
the measuring tool is correctly assembled before
taking any measurements.
24.Take care when removing or installing the tracks
of track-type machines.
When removing the track, the track separates
suddenly, so never let anyone stand at either
end of the track.
FOREWORD
GENERAL
FOREWORD
GENERAL
This shop manual has been prepared as an aid to improve the quality of repairs by giving the serviceman an
accurate understanding of the product and by showing him the correct way to perform repairs and make judgements. Make sure you understand the contents of this manual and use it to full effect at every opportunity.
This shop manual mainly contains the necessary technical information for operations performed in a service
workshop. For ease of understanding, the manual is divided into the following chapters; these chapters are further divided into the each main group of components.
STRUCTURE AND FUNCTION
This section explains the structure and function of each component. It serves not only to give an understanding of the structure, but also serves as reference material for troubleshooting.
In addition, this section may contain hydraulic circuit diagrams, electric circuit diagrams, and maintenance standards.
TESTING AND ADJUSTING
This section explains checks to be made before and after performing repairs, as well as adjustments to
be made at completion of the checks and repairs.
Troubleshooting charts correlating "Problems" with "Causes" are also included in this section.
DISASSEMBLY AND ASSEMBLY
This section explains the procedures for removing, installing, disassembling and assembling each component, as well as precautions for them.
MAINTENANCE STANDARD
This section gives the judgment standards for inspection of disassembled parts.
The contents of this section may be described in STRUCTURE AND FUNCTION.
OTHERS
This section mainly gives hydraulic circuit diagrams and electric circuit diagrams.
In addition, this section may give the specifications of attachments and options together.
NOTICE
The specifications contained in this shop manual are subject to change at any time and without any
advance notice. Use the specifications given in the book with the latest date.
00-5
FOREWORD
HOW TO READ THE SHOP MANUAL
HOW TO READ THE SHOP MANUAL
REVISED EDITION MARK
VOLUMES
Shop manuals are issued as a guide to carrying out
repairs. They are divided as follows:
When a manual is revised, an edition mark
((1)(2)(3)....) is recorded on the bottom of the pages.
Chassis volume: Issued for every machine model
Engine volume: Issued for each engine series
Each issued as one
Electrical volume:
Attachments volume: · volume to cover all
models
REVISIONS
}
These various volumes are designed to avoid duplicating the same information. Therefore, to deal with
all repairs for any model , it is necessary that chassis, engine, electrical and attachment volumes be
available.
DISTRIBUTION AND UPDATING
Any additions, amendments or other changes will be
sent to KOMATSU distributors. Get the most up-todate information before you start any work.
FILING METHOD
1. See the page number on the bottom of the page.
File the pages in correct order.
2. Following examples show how to read the page
number.
Example 1 (Chassis volume):
10 - 3
Item number (10. Structure and
Function)
Consecutive page number for each
item.
Example 2 (Engine volume):
12 - 5
Unit number (1. Engine)
Item number (2. Testing and Adjusting)
Consecutive page number for each
item.
3. Additional pages: Additional pages are indicated
by a hyphen (-) and number after the page
number. File as in the example.
Example:
12-203
10-4
12-203-1
10-4-1
Added pages
12-203-2
10-4-2
12-204
10-5
00-6
Revised pages are shown in the LIST OF REVISED
PAGES next to the CONTENTS page.
SYMBOLS
So that the shop manual can be of ample practical
use, important safety and quality portions are
marked with the following symbols.
Symbol
Item
Remarks
k
Safety
Special safety precautions
are necessary when performing the work.
Caution
Special technical precautions or other precautions
for preserving standards
are necessary when performing the work.
Weight
Weight of parts of systems. Caution necessary
when selecting hoisting
wire, or when working posture is important, etc.
Tightening
torque
Places that require special
attention for the tightening
torque during assembly.
Coat
Places to be coated with
adhesives and lubricants,
etc.
5
Oil, water
Places where oil, water or
fuel must be added, and
the capacity.
6
Drain
Places where oil or water
must be drained, and
quantity to be drained.
a
4
3
2
FOREWORD
HOISTING INSTRUCTIONS
HOISTING INSTRUCTIONS
HOISTING
k Heavy parts (25 kg or more) must be lifted
with a hoist, etc. In the DISASSEMBLY
AND ASSEMBLY section, every part
weighing 25 kg or more is indicated clearly
with the symbol 4
•
If a part cannot be smoothly removed from the
machine by hoisting, the following checks
should be made:
1) Check for removal of all bolts fastening the
part to the relative parts.
2) Check for existence of another part causing
interference with the part to be removed.
WIRE ROPES
1) Use adequate ropes depending on the
weight of parts to be hoisted, referring to
the table below:
Wire ropes
(Standard "Z" or "S" twist ropes
without galvanizing)
Rope diameter
Allowable load
mm
kN
tons
10
11.5
12.5
14
16
18
20
22.4
30
40
50
60
9.8
13.7
15.7
21.6
27.5
35.3
43.1
54.9
98.1
176.5
274.6
392.2
1.0
1.4
1.6
2.2
2.8
3.6
4.4
5.6
10.0
18.0
28.0
40.0
Slinging near the edge of the hook may cause
the rope to slip off the hook during hoisting, and
a serious accident can result. Hooks have maximum strength at the middle portion.
100%
88%
79%
71%
41%
SAD00479
3) Do not sling a heavy load with one rope alone,
but sling with two or more ropes symmetrically
wound onto the load.
k Slinging with one rope may cause turning
of the load during hoisting, untwisting of
the rope, or slipping of the rope from its
original winding position on the load, which
can result in a dangerous accident.
4) Do not sling a heavy load with ropes forming a
wide hanging angle from the hook.
When hoisting a load with two or more ropes,
the force subjected to each rope will increase
with the hanging angles. The table below
shows the variation of allowable load kN {kg}
when hoisting is made with two ropes, each of
which is allowed to sling up to 9.8 kN {1000 kg}
vertically, at various hanging angles.
When two ropes sling a load vertically, up to
19.6 kN {2000 kg} of total weight can be suspended. This weight becomes 9.8 kN {1000 kg}
when two ropes make a 120° hanging angle.
On the other hand, two ropes are subjected to
an excessive force as large as 39.2 kN {4000
kg} if they sling a 19.6 kN {2000 kg} load at a
lifting angle of 150°.
★ The allowable load value is estimated to be onesixth or one-seventh of the breaking strength of
the rope used.
2) Sling wire ropes from the middle portion of the
hook.
00-7
FOREWORD
METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER
METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER
k Before carrying out the following work, release
the residual pressure from the hydraulic tank.
For details, see TESTING AND ADJUSTING,
Releasing residual pressure from hydraulic
tank.
k Even if the residual pressure is released from
the hydraulic tank, some hydraulic oil flows out
when the hose is disconnected. Accordingly,
prepare an oil receiving container.
Disconnection
1) Release the residual pressure from the hydraulic tank. For details, see TESTING AND
ADJUSTING, Releasing residual pressure from
hydraulic tank.
2) Hold adapter (1) and push hose joint (2) into
mating adapter (3). (See Fig. 1)
★ The adapter can be pushed in about 3.5
mm.
★ Do not hold rubber cap portion (4).
3) After hose joint (2) is pushed into adapter (3),
press rubber cap portion (4) against (3) until it
clicks. (See Fig. 2)
4) Hold hose adapter (1) or hose (5) and pull it out.
(See Fig. 3)
★ Since some hydraulic oil flows out, prepare
an oil receiving container.
Connection
1) Hold hose adapter (1) or hose (5) and insert it in
mating adapter (3), aligning them with each
other. (See Fig. 4)
★ Do not hold rubber cap portion (4).
2) After inserting the hose in the mating adapter
perfectly, pull it back to check its connecting
condition. (See Fig. 5)
★ When the hose is pulled back, the rubber
cap portion moves toward the hose about
3.5 mm. This does not indicate abnormality,
however.
00-8
Type 1
FOREWORD
METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER
Type 3
1) Hold the mouthpiece of the tightening portion
and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of
the hexagonal portion at the male end.
1) Hold the mouthpiece of the tightening portion
and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of
the hexagonal portion at the male end.
2) Hold in the condition in Step 1), and turn
lever (4) to the right (clockwise).
2) Hold in the condition in Step 1), and push
until cover (3) contacts contact surface a of
the hexagonal portion at the male end.
3) Hold in the condition in Steps 1) and 2), and
pull out whole body (2) to disconnect it.
3) Hold in the condition in Steps 1) and 2), and
pull out whole body (2) to disconnect it.
•
•
Disassembly
Type 2
Hold the mouthpiece of the tightening portion
and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of
the hexagonal portion at the male end to connect it.
Connection
Hold the mouthpiece of the tightening portion
and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of
the hexagonal portion at the male end to connect it.
00-9
FOREWORD
COATING MATERIALS
COATING MATERIALS
★ The recommended coating materials such as adhesives, gasket sealants and greases used for disassembly
and assembly are listed below.
★ For coating materials not listed below, use the equivalent of products shown in this list.
Category
Komatsu code
Part No.
Q'ty
Container
Main applications, features
LT-1A
790-129-9030
150 g
Tube
• Used to prevent rubber gaskets, rubber cushions, and cock plug from
coming out.
LT-1B
790-129-9050
20 g
(2 pcs.)
Polyethylene
container
• Used in places requiring an immediately effective, strong adhesive.
Used for plastics (except polyethylene, polyprophylene, tetrafluoroethlene and vinyl chloride), rubber,
metal and non-metal.
LT-2
09940-00030
50 g
Polyethylene
container
• Features: Resistance to heat and
chemicals
• Used for anti-loosening and sealant
purpose for bolts and plugs.
LT-3
790-129-9060
(Set of adhesive
and hardening
agent)
Adhesive:
1 kg
Hardening
agent:
500 g
Can
LT-4
790-129-9040
250 g
Polyethylene
container
Holtz
MH 705
790-126-9120
75 g
Tube
• Used as heat-resisting sealant for repairing engine.
50 g
Polyethylene
container
• Quick hardening type adhesive
• Cure time: within 5 sec. to 3 min.
• Used mainly for adhesion of metals,
rubbers, plastics and woods.
Adhesives
Three bond
1735
790-129-9140
• Used as adhesive or sealant for metal, glass and plastic.
Aron-alpha
201
790-129-9130
2g
Polyethylene
container
• Quick hardening type adhesive
• Quick cure type (max. strength after
30 minutes)
• Used mainly for adhesion of rubbers,
plastics and metals.
Loctite
648-50
79A-129-9110
50 cc
Polyethylene
container
• Resistance to heat, chemicals
• Used at joint portions subject to high
temperatures.
LG-1
790-129-9010
200 g
Tube
• Used as adhesive or sealant for gaskets and packing of power train case,
etc.
LG-5
790-129-9080
1 kg
Can
• Used as sealant for various threads,
pipe joints, flanges.
• Used as sealant for tapered plugs,
elbows, nipples of hydraulic piping.
Tube
• Features: Silicon based, resistance
to heat, cold
• Used as sealant for flange surface,
tread.
• Used as sealant for oil pan, final
drive case, etc.
LG-6
790-129-9020
200 g
Gasket
sealant
LG-7
790-129-9070
1 kg
Tube
• Features: Silicon based, quick hardening type
• Used as sealant for flywheel housing, intake manifold, oil pan, thermostat housing, etc.
Three bond
1211
790-129-9090
100 g
Tube
• Used as heat-resisting sealant for repairing engine.
Tube
• Features: Silicone type, heat resistant, vibration resistant, and impact
resistant sealing material
• Used as sealing material for transfer
case
Three bond
1207B
00-10
• Used as sealant for machined holes.
419-15-18131
100 g
FOREWORD
Molybdenum
disulphide
lubricant
Grease
Primer
Adhesive
Caulking
material
Komatsu code
Part No.
Q'ty
Container
Main applications, features
LM-G
09940-00051
60 g
Can
• Used as lubricant for sliding portion
(to prevent from squeaking).
Tube
• Used to prevent seizure or scuffling
of the thread when press fitting or
shrink fitting.
• Used as lubricant for linkage, bearings, etc.
LM-P
09940-00040
G2-LI
SYG2-400LI
SYG2-350LI
SYG2-400LI-A
SYG2-160LI
SYGA-160CNLI
G2-CA
SYG2-400CA
SYG2-350CA
SYG2-400CA-A
SYG2-160CA
SYGA-160CNCA
Molybdenum
disulphide
grease
LM-G (G2-M)
SYG2-400M
SYG2-400M-A
SYGA-16CNM
Hyper White
Grease G2-T
G0-T (*)
*: For use in cold
district
SYG2-400T-A
SYG2-16CNT
SYG0-400T-A (*)
SYG0-16CNT (*)
Biogrease G2B
G2-BT (*)
*: For high
temperature
and large load
SYG2-400B
SYGA-16CNB
SYG2-400BT (*)
SYGA-16CNBT (*)
200 g
• General purpose type
Various
Various
Various
Various
400 g × 10 Bellows type
400 g × 20 Bellows type
16 kg
Can
400 g
16 kg
400 g
16 kg
• Since this grease is decomposed
by bacteria in short period, it has
Bellows type
less effects on microorganisms,
Can
animals, and plants.
20 ml
Glass
container
SUNSTAR
GLASS PRIMER
580 SUPER
20 ml
Glass
container
SUNSTAR
PENGUINE
SEAL 580
SUPER "S" or
"W"
• Used for heavy load portion
• Seizure resistance and heat resistance higher than molybdenum diBellows type
sulfide grease
Can
• Since this grease is white, it does
not stand out against machine
body.
SUNSTAR
PAINT PRIMER
580 SUPER
417-926-3910
• Used for normal temperature, light
load bearing at places in contact
with water or steam.
320 ml
Polyethylene
container
Sika Japan,
Sikaflex 256HV
20Y-54-39850
310 ml
Polyethylene
container
SUNSTAR
PENGUINE
SEAL No. 2505
417-926-3920
320 ml
Polyethylene
container
SEKISUI
SILICONE
SEALANT
20Y-54-55130
333 ml
Polyethylene
container
• Used as primer for cab side
(Using limit: 4 months)
• Used as primer for glass side
(Using limit: 4 months)
Adhesive for cab glass
Category
COATING MATERIALS
• "S" is used for high-temperature season (April - October)
and "W" for low-temperature
season (November - April) as
adhesive for glass.
(Using limit: 4 months)
• Used as adhesive for glass.
(Using limit: 6 months)
• Used to seal joints of glass
parts.
(Using limit: 4 months)
• Used to seal front window.
(Using limit: 6 months)
00-11
FOREWORD
STANDARD TIGHTENING TORQUE
STANDARD TIGHTENING TORQUE
STANDARD TIGHTENING TORQUE TABLE (WHEN USING TORQUE WRENCH)
★ In the case of metric nuts and bolts for which there is no special instruction, tighten to the torque given in
the table below.
Tightening torque
Thread diameter
of bolt
Width across
flats
mm
mm
Nm
kgm
6
8
10
12
14
10
13
17
19
22
11.8 – 14.7
27 – 34
59 – 74
98 – 123
153 – 190
1.2 – 1.5
2.8 – 3.5
6 – 7.5
10 – 12.5
15.5 – 19.5
16
18
20
22
24
24
27
30
32
36
235 – 285
320 – 400
455 – 565
610 – 765
785 – 980
23.5 – 29.5
33 – 41
46.5 – 58
62.5 – 78
80 – 100
27
30
33
36
39
41
46
50
55
60
1150 – 1440
1520 – 1910
1960 – 2450
2450 – 3040
2890 – 3630
118 – 147
155 – 195
200 – 250
250 – 310
295 – 370
Thread diameter
of bolt
Width across
flats
mm
mm
Nm
kgm
6
8
10
12
10
13
14
27
5.9 – 9.8
13.7 – 23.5
34.3 – 46.1
74.5 – 90.2
0.6 – 1.0
1.4 – 2.4
3.5 – 4.7
7.6 – 9.2
Tightening torque
Sealing surface
TABLE OF TIGHTENING TORQUES FOR FLARED NUTS
★ In the case of flared nuts for which there is no
special instruction, tighten to the torque given in
the table below.
SAD00483
Thread diameter
Width across flat
mm
mm
Nm
kgm
14
18
22
24
30
33
36
42
19
24
27
32
36
41
46
55
24.5 ± 4.9
49 ± 19.6
78.5 ± 19.6
137.3 ± 29.4
176.5 ± 29.4
196.1 ± 49
245.2 ± 49
294.2 ± 49
2.5 ± 0.5
5±2
8±2
14 ± 3
18 ± 3
20 ± 5
25 ± 5
30 ± 5
00-12
Tightening torque
FOREWORD
STANDARD TIGHTENING TORQUE
TABLE OF TIGHTENING TORQUES FOR SPLIT FLANGE BOLTS
★ In the case of split flange bolts for which there is no special instruction, tighten to the torque given in the
table below.
Thread diameter
Width across flat
Tightening torque
mm
mm
Nm
kgm
10
12
16
14
17
22
59 – 74
98 – 123
235 – 285
6 – 7.5
10 – 12.5
23.5 – 29.5
TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PIPING JOINTS
★ Unless there are special instructions, tighten the O-ring boss piping joints to the torque below.
Thread diameter
Width across flat
mm
mm
14
20
24
33
42
Varies depending
on type of
connector.
Tightening torque (Nm {kgm})
Norminal No.
02
03, 04
05, 06
10, 12
14
Range
35 – 63
84 – 132
128 – 186
363 – 480
746 – 1010
{3.5 – 6.5}
{8.5 – 13.5}
{13.0 – 19.0}
{37.0 – 49.0}
{76.0 – 103}
Target
44 {4.5}
103 {10.5}
157 {16.0}
422 {43.0}
883 {90.0}
TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PLUGS
★ Unless there are special instructions, tighten the O-ring boss plugs to the torque below.
Thread diameter
Width across flat
mm
mm
08
10
12
14
16
18
20
24
30
33
36
42
52
14
17
19
22
24
27
30
32
32
—
36
—
—
Tightening torque (Nm {kgm})
Norminal No.
08
10
12
14
16
18
20
24
30
33
36
42
52
Range
5.88 – 8.82
9.8 – 12.74
14.7 – 19.6
19.6 – 24.5
24.5 – 34.3
34.3 – 44.1
44.1 – 53.9
58.8 – 78.4
93.1 – 122.5
107.8 – 147.0
127.4 – 176.4
181.3 – 240.1
274.4 – 367.5
{0.6 – 0.9}
{1.0 – 1.3}
{1.5 – 2.0}
{2.0 – 2.5}
{2.5 – 3.5}
{3.5 – 4.5}
{4.5 – 5.5}
{6.0 – 8.0}
{9.5 – 12.5}
{11.0 – 15.0}
{13.0 – 18.0}
{18.5 – 24.5}
{28.0 – 37.5}
Target
7.35 {0.75}
11.27 {1.15}
17.64 {1.8}
22.54 {2.3}
29.4 {3.0}
39.2 {4.0}
49.0 {5.0}
68.6 {7.0}
107.8 {11.0}
124.4 {13.0}
151.9 {15.5}
210.7 {21.5}
323.4 {33.0}
00-13
FOREWORD
STANDARD TIGHTENING TORQUE
TIGHTENING TORQUE FOR 102 ENGINE SERIES
1) BOLT AND NUTS
Use these torques for bolts and nuts (unit: mm) of Cummins Engine.
Thread diameter
Tightening torque
mm
Nm
kgm
10 0 2
24 0 4
43 0 6
77 0 12
6
8
10
12
1.02 0 0.20
2.45 0 0.41
4.38 0 0.61
7.85 0 1.22
2) EYE JOINTS
Use these torques for eye joints (unit: mm) of Cummins Engine.
Thread diameter
Tightening torque
mm
Nm
kgm
802
10 0 2
12 0 2
24 0 4
36 0 5
6
8
10
12
14
0.81 0 0.20
1.02 0 0.20
1.22 0 0.20
2.45 0 0.41
3.67 0 0.51
3) TAPERED SCREWS
Use these torques for tapered screws (unit: inch) of Cummins Engine.
Thread diameter
Tightening torque
inch
Nm
kgm
301
802
12 0 2
15 0 2
24 0 4
36 0 5
60 0 9
1 / 16
1/8
1/4
3/8
1/2
3/4
1
0.31 0 0.10
0.81 0 0.20
1.22 0 0.20
1.53 0 0.41
2.45 0 0.41
3.67 0 0.51
6.12 0 0.92
TIGHTENING TORQUE TABLE FOR HOSES (TAPER SEAL TYPE AND FACE SEAL TYPE)
★ Tighten the hoses (taper seal type and face seal type) to the following torque, unless otherwise specified.
★ Apply the following torque when the threads are coated (wet) with engine oil.
Tightening torque (Nm {kgm})
Nominal size Width across
of hose
flats
Taper seal
type
Face seal type
Nominal thread
Thread size size
Root diameter
- Threads per
(mm)
inch, Thread series (mm) (Reference)
Range
Target
34 – 54 {3.5 – 5.5}
44 {4.5}
–
9
— – 18UN
16
14.3
34 – 63 {3.5 – 6.5}
44 {4.5}
14
–
–
22
54 – 93 {5.5 – 9.5}
74 {7.5}
–
11
— – 16UN
16
17.5
24
59 – 98 {6.0 – 10.0}
78 {8.0}
18
–
–
04
27
84 – 132 {8.5 – 13.5}
103 {10.5}
22
13
— – 16UN
16
20.6
05
32
128 – 186 {13.0 – 19.0}
157 {16.0}
24
1 – 14UNS
25.4
06
36
177 – 245 {18.0 – 25.0}
216 {22.0}
30
3
1 — – 12UN
16
30.2
(10)
41
177 – 245 {18.0 – 25.0}
216 {22.0}
33
–
–
(12)
46
197 – 294 {20.0 – 30.0}
245 {25.0}
36
–
–
(14)
55
246 – 343 {25.0 – 35.0}
294 {30.0}
42
–
–
02
03
00-14
19
FOREWORD
ELECTRIC WIRE CODE
ELECTRIC WIRE CODE
In the wiring diagrams, various colors and symbols are employed to indicate the thickness of wires.
This wire code table will help you understand WIRING DIAGRAMS.
Example: 5WB indicates a cable having a nominal number 5 and white coating with black stripe.
CLASSIFICATION BY THICKNESS
Copper wire
Cable O.D.
(mm)
Current
rating
(A)
Applicable circuit
0.88
2.4
12
Starting, lighting, signal
etc.
0.32
2.09
3.1
20
Lighting, signal etc.
65
0.32
5.23
4.6
37
Charging and signal
15
84
0.45
13.36
7.0
59
Starting (Glow plug)
40
85
0.80
42.73
11.4
135
Starting
60
127
0.80
63.84
13.6
178
Starting
100
217
0.80
109.1
17.6
230
Starting
Norminal
number
Number of
strands
Dia. of
strands
(mm2)
Cross
section
(mm2)
0.85
11
0.32
2
26
5
CLASSIFICATION BY COLOR AND CODE
Circuits
Priority
Classification
1
Primary
Charging
Ground
Starting
Lighting
Instrument
Signal
Other
Code
W
B
B
R
Y
G
L
Color
White
Black
Black
Red
Yellow
Green
Blue
Code
WR
—
BW
RW
YR
GW
LW
2
Color White & Red
—
Code
—
WB
White & Black Red & White Rellow & Red Green & White Blue & White
BY
RB
YB
GR
LR
3
4
Auxiliary
Color White & Black
—
Code
—
WL
Black & Yellow Red & Black Yellow & Black Green & Red Blue & Yellow
BR
Color White & Blue
—
Code
—
—
Color White & Green
—
—
Code
—
—
—
Color
—
—
—
WG
RY
Black & Red Red & Yellow
RG
YG
GY
LY
Yellow &
Green
Green &
Yellow
Blue & Yellow
YL
GB
LB
5
Red & Green Yellow & Blue Green & Black Blue & Black
RL
YW
GL
6
Red & Blue Yellow & White Green & Blue
n
n
00-15
FOREWORD
CONVERSION TABLE
CONVERSION TABLE
METHOD OF USING THE CONVERSION TABLE
The Conversion Table in this section is provided to enable simple conversion of figures. For details of the
method of using the Conversion Table, see the example given below.
EXAMPLE
• Method of using the Conversion Table to convert from millimeters to inches
1. Convert 55 mm into inches.
(1) Locate the number 50 in the vertical column at the left side, take this as A, then draw a horizontal line
from A.
(2) Locate the number 5 in the row across the top, take this as B, then draw a perpendicular line down
from B.
(3) Take the point where the two lines cross as C. This point C gives the value when converting from millimeters to inches. Therefore, 55 mm = 2.165 inches.
2. Convert 550 mm into inches.
(1) The number 550 does not appear in the table, so divide by 10 (move the decimal point one place to the
left) to convert it to 55 mm.
(2) Carry out the same procedure as above to convert 55 mm to 2.165 inches.
(3) The original value (550 mm) was divided by 10, so multiply 2.165 inches by 10 (move the decimal point
one place to the right) to return to the original value. This gives 550 mm = 21.65 inches.
B
Millimeters to inches
1 mm = 0.03937 in
A
00-16
0
1
2
3
4
0
10
20
30
40
0
0.394
0.787
1.181
1.575
0.039
0.433
0.827
1.220
1.614
0.079
0.472
0.866
1.260
1.654
0.118
0.512
0.906
1.299
1.693
0.157
0.551
0.945
1.339
1.732
50
60
70
80
90
1.969
2.362
2.756
3.150
3.543
2.008
2.402
2.795
3.189
3.583
2.047
2.441
2.835
3.228
3.622
2.087
2.480
2.874
3.268
3.661
2.126
2.520
2.913
3.307
3.701
5
0.197
0.591
0.984
1.378
1.772
C
2.165
2.559
2.953
3.346
3.740
6
7
8
9
0.236
0.630
1.024
1.417
1.811
0.276
0.669
1.063
1.457
1.850
0.315
0.709
1.102
1.496
1.890
0.354
0.748
1.142
1.536
1.929
2.205
2.598
2.992
3.386
3.780
2.244
2.638
3.032
3.425
3.819
2.283
2.677
3.071
3.465
3.858
2.323
2.717
3.110
3.504
3.898
FOREWORD
CONVERSION TABLE
Millimeters to Inches
1 mm = 0.03937 in
0
1
2
3
4
5
6
7
8
9
0
0.039
0.079
0.118
0.157
0.197
0.236
0.276
0.315
0.354
10
0.394
0.433
0.472
0.512
0.551
0.591
0.630
0.669
0.709
0.748
20
0.787
0.827
0.866
0.906
0.945
0.984
1.024
1.063
1.102
1.142
30
1.181
1.220
1.260
1.299
1.339
1.378
1.417
1.457
1.496
1.536
40
1.575
1.614
1.654
1.693
1.732
1.772
1.811
1.850
1.890
1.929
50
1.969
2.008
2.047
2.087
2.126
2.165
2.205
2.244
2.283
2.323
60
2.362
2.402
2.441
2.480
2.520
2.559
2.598
2.638
2.677
2.717
70
2.756
2.795
2.835
2.874
2.913
2.953
2.992
3.032
3.071
3.110
80
3.150
3.189
3.228
3.268
3.307
3.346
3.386
3.425
3.465
3.504
90
3.543
3.583
3.622
3.661
3.701
3.740
3.780
3.819
3.858
3.898
0
Kilogram to Pound
1 kg = 2.2046 lb
0
0
0
1
2
3
4
5
6
7
8
9
2.20
4.41
6.61
8.82
11.02
13.23
15.43
17.64
19.84
10
22.05
24.25
26.46
28.66
30.86
33.07
35.27
37.48
39.68
41.89
20
44.09
46.30
48.50
50.71
51.91
55.12
57.32
59.53
61.73
63.93
30
66.14
68.34
70.55
72.75
74.96
77.16
79.37
81.57
83.78
85.98
40
88.18
90.39
92.59
94.80
97.00
99.21
101.41
103.62
105.82
108.03
50
110.23
112.44
114.64
116.85
119.05
121.25
123.46
125.66
127.87
130.07
60
132.28
134.48
136.69
138.89
141.10
143.30
145.51
147.71
149.91
152.12
70
154.32
156.53
158.73
160.94
163.14
165.35
167.55
169.76
171.96
174.17
80
176.37
178.57
180.78
182.98
185.19
187.39
189.60
191.80
194.01
196.21
90
198.42
200.62
202.83
205.03
207.24
209.44
211.64
213.85
216.05
218.26
00-17
FOREWORD
CONVERSION TABLE
Liter to U.S. Gallon
1l = 0.2642 U.S. Gal
0
1
2
3
4
5
6
7
8
9
0
0.264
0.528
0.793
1.057
1.321
1.585
1.849
2.113
2.378
10
2.642
2.906
3.170
3.434
3.698
3.963
4.227
4.491
4.755
5.019
20
5.283
5.548
5.812
6.076
6.340
6.604
6.869
7.133
7.397
7.661
30
7.925
8.189
8.454
8.718
8.982
9.246
9.510
9.774
10.039
10.303
40
10.567
10.831
11.095
11.359
11.624
11.888
12.152
12.416
12.680
12.944
50
13.209
13.473
13.737
14.001
14.265
14.529
14.795
15.058
15.322
15.586
60
15.850
16.115
16.379
16.643
16.907
17.171
17.435
17.700
17.964
18.228
70
18.492
18.756
19.020
19.285
19.549
19.813
20.077
20.341
20.605
20.870
80
21.134
21.398
21.662
21.926
22.190
22.455
22.719
22.983
23.247
23.511
90
23.775
24.040
24.304
24.568
24.832
25.096
25.361
25.625
25.889
26.153
0
Liter to U.K. Gallon
1l = 0.21997 U.K. Gal
0
1
2
3
4
5
6
7
8
9
0
0.220
0.440
0.660
0.880
1.100
1.320
1.540
1.760
1.980
10
2.200
2.420
2.640
2.860
3.080
3.300
3.520
3.740
3.950
4.179
20
4.399
4.619
4.839
5.059
5.279
5.499
5.719
5.939
6.159
6.379
30
6.599
6.819
7.039
7.259
7.479
7.969
7.919
8.139
8.359
8.579
40
8.799
9.019
9.239
9.459
9.679
9.899
10.119
10.339
10.559
10.778
50
10.998
11.281
11.438
11.658
11.878
12.098
12.318
12.528
12.758
12.978
60
13.198
13.418
13.638
13.858
14.078
14.298
14.518
14.738
14.958
15.178
70
15.398
15.618
15.838
16.058
16.278
16.498
16.718
16.938
17.158
17.378
80
17.598
17.818
18.037
18.257
18.477
18.697
18.917
19.137
19.357
19.577
90
19.797
20.017
20.237
20.457
20.677
20.897
21.117
21.337
21.557
21.777
0
00-18
FOREWORD
CONVERSION TABLE
kgm to ft. lb
1 kgm = 7.233 ft. lb
0
1
2
3
4
5
6
7
8
9
0
0
7.2
14.5
21.7
28.9
36.2
43.4
50.6
57.9
65.1
10
72.3
79.6
86.8
94.0
101.3
108.5
115.7
123.0
130.2
137.4
20
144.7
151.9
159.1
166.4
173.6
180.8
188.1
195.3
202.5
209.8
30
217.0
224.2
231.5
238.7
245.9
253.2
260.4
267.6
274.9
282.1
40
289.3
296.6
303.8
311.0
318.3
325.5
332.7
340.0
347.2
354.4
50
361.7
368.9
376.1
383.4
390.6
397.8
405.1
412.3
419.5
426.8
60
434.0
441.2
448.5
455.7
462.9
470.2
477.4
484.6
491.8
499.1
70
506.3
513.5
520.8
528.0
535.2
542.5
549.7
556.9
564.2
571.4
80
578.6
585.9
593.1
600.3
607.6
614.8
622.0
629.3
636.5
643.7
90
651.0
658.2
665.4
672.7
679.9
687.1
694.4
701.6
708.8
716.1
100
723.3
730.5
737.8
745.0
752.2
759.5
766.7
773.9
781.2
788.4
110
795.6
802.9
810.1
817.3
824.6
831.8
839.0
846.3
853.5
860.7
120
868.0
875.2
882.4
889.7
896.9
904.1
911.4
918.6
925.8
933.1
130
940.3
947.5
954.8
962.0
969.2
976.5
983.7
990.9
998.2
1005.4
140
1012.6
1019.9
1027.1
1034.3
1041.5
1048.8
1056.0
1063.2
1070.5
1077.7
150
1084.9
1092.2
1099.4
1106.6
1113.9
1121.1
1128.3
1135.6
1142.8
1150.0
160
1157.3
1164.5
1171.7
1179.0
1186.2
1193.4
1200.7
1207.9
1215.1
1222.4
170
1129.6
1236.8
1244.1
1251.3
1258.5
1265.8
1273.0
1280.1
1287.5
1294.7
180
1301.9
1309.2
1316.4
1323.6
1330.9
1338.1
1345.3
1352.6
1359.8
1367.0
190
1374.3
1381.5
1388.7
1396.0
1403.2
1410.4
1417.7
1424.9
1432.1
1439.4
00-19
FOREWORD
CONVERSION TABLE
kg/cm2 to lb/in2
1kg/cm2 = 14.2233 lb/in2
0
1
2
3
4
5
6
7
8
9
0
0
14.2
28.4
42.7
56.9
71.1
85.3
99.6
113.8
128.0
10
142.2
156.5
170.7
184.9
199.1
213.4
227.6
241.8
256.0
270.2
20
284.5
298.7
312.9
327.1
341.4
355.6
369.8
384.0
398.3
412.5
30
426.7
440.9
455.1
469.4
483.6
497.8
512.0
526.3
540.5
554.7
40
568.9
583.2
597.4
611.6
625.8
640.1
654.3
668.5
682.7
696.9
50
711.2
725.4
739.6
753.8
768.1
782.3
796.5
810.7
825.0
839.2
60
853.4
867.6
881.8
896.1
910.3
924.5
938.7
953.0
967.2
981.4
70
995.6
1010
1024
1038
1053
1067
1081
1095
1109
1124
80
1138
1152
1166
1181
1195
1209
1223
1237
1252
1266
90
1280
1294
1309
1323
1337
1351
1365
1380
1394
1408
100
1422
1437
1451
1465
1479
1493
1508
1522
1536
1550
110
1565
1579
1593
1607
1621
1636
1650
1664
1678
1693
120
1707
1721
1735
1749
1764
1778
1792
1806
1821
1835
130
1849
1863
1877
1892
1906
1920
1934
1949
1963
1977
140
1991
2005
2020
2034
2048
2062
2077
2091
2105
2119
150
2134
2148
2162
2176
2190
2205
2219
2233
2247
2262
160
2276
2290
2304
2318
2333
2347
2361
2375
2389
2404
170
2418
2432
2446
2460
2475
2489
2503
2518
2532
2546
180
2560
2574
2589
2603
2617
2631
2646
2660
2674
2688
190
2702
2717
2731
2745
2759
2773
2788
2802
2816
2830
200
2845
2859
2873
2887
2901
2916
2930
2944
2958
2973
210
2987
3001
3015
3030
3044
3058
3072
3086
3101
3115
220
3129
3143
3158
3172
3186
3200
3214
3229
3243
3257
230
3271
3286
3300
3314
3328
3343
3357
3371
3385
3399
240
3414
3428
3442
3456
3470
3485
3499
3513
3527
3542
00-20
FOREWORD
CONVERSION TABLE
Temperature
Fahrenheit-Centigrade Conversion ; a simple way to convert a Fahrenheit temperature reading into a Centigrade temperature reading or vice versa is to enter the accompanying table in the center or boldface column of figures.
These figures refer to the temperature in either Fahrenheit or Centigrade degrees.
If it is desired to convert from Fahrenheit to Centigrade degrees, consider the center column as a table of
Fahrenheit temperatures and read the corresponding Centigrade temperature in the column at the left.
If it is desired to convert from Centigrade to Fahrenheit degrees, consider the center column as a table of
Centigrade values, and read the corresponding Fahrenheit temperature on the right.
1°C = 33.8°F
°C
°F
°C
°F
°C
°F
°C
°F
–40.4
–37.2
–34.4
–31.7
–28.9
–40
–35
–30
–25
–20
–40.0
–31.0
–22.0
–13.0
–4.0
–11.7
–11.1
–10.6
–10.0
–9.4
11
12
13
14
15
51.8
53.6
55.4
57.2
59.0
7.8
8.3
8.9
9.4
10.0
46
47
48
49
50
114.8
116.6
118.4
120.2
122.0
27.2
27.8
28.3
28.9
29.4
81
82
83
84
85
117.8
179.6
181.4
183.2
185.0
–28.3
–27.8
–27.2
–26.7
–26.1
–19
–18
–17
–16
–15
–2.2
–0.4
1.4
3.2
5.0
–8.9
–8.3
–7.8
–7.2
–6.7
16
17
18
19
20
60.8
62.6
64.4
66.2
68.0
10.6
11.1
11.7
12.2
12.8
51
52
53
54
55
123.8
125.6
127.4
129.2
131.0
30.0
30.6
31.1
31.7
32.2
86
87
88
89
90
186.8
188.6
190.4
192.2
194.0
–25.6
–25.0
–24.4
–23.9
–23.3
–14
–13
–12
–11
–10
6.8
8.6
10.4
12.2
14.0
–6.1
–5.6
–5.0
–4.4
–3.9
21
22
23
24
25
69.8
71.6
73.4
75.2
77.0
13.3
13.9
14.4
15.0
15.6
56
57
58
59
0
132.8
134.6
136.4
138.2
140.0
32.8
33.3
33.9
34.4
35.0
91
92
93
94
95
195.8
197.6
199.4
201.2
203.0
–22.8
–22.2
–21.7
–21.1
–20.6
–9
–8
–7
–6
–5
15.8
17.6
19.4
21.2
23.0
–3.3
–2.8
–2.2
–1.7
–1.1
26
27
28
29
30
78.8
80.6
82.4
84.2
86.0
16.1
16.7
17.2
17.8
18.3
61
62
63
64
65
141.8
143.6
145.4
147.2
149.0
35.6
36.1
36.7
37.2
37.8
96
97
98
99
100
204.8
206.6
208.4
210.2
212.0
–20.0
–19.4
–18.9
–18.3
–17.8
–4
–3
–2
–1
0
24.8
26.6
28.4
30.2
32.0
–0.6
0
0.6
1.1
1.7
31
32
33
34
35
87.8
89.6
91.4
93.2
95.0
18.9
19.4
20.0
20.6
21.1
66
67
68
69
70
150.8
152.6
154.4
156.2
158.0
40.6
43.3
46.1
48.9
51.7
105
110
115
120
125
221.0
230.0
239.0
248.0
257.0
–17.2
–16.7
–16.1
–15.6
–15.0
1
2
3
4
5
33.8
35.6
37.4
39.2
41.0
2.2
2.8
3.3
3.9
4.4
36
37
38
39
40
96.8
98.6
100.4
102.2
104.0
21.7
22.2
22.8
23.3
23.9
71
72
73
74
75
159.8
161.6
163.4
165.2
167.0
54.4
57.2
60.0
62.7
65.6
130
135
140
145
150
266.0
275.0
284.0
293.0
302.0
–14.4
–13.9
–13.3
–12.8
–12.2
6
7
8
9
10
42.8
44.6
46.4
48.2
50.0
5.0
5.6
6.1
6.7
7.2
41
42
43
44
45
105.8
107.6
109.4
111.2
113.0
24.4
25.0
25.6
26.1
26.7
76
77
78
79
80
168.8
170.6
172.4
174.2
176.0
68.3
71.1
73.9
76.7
79.4
155
160
165
170
175
311.0
320.0
329.0
338.0
347.0
00-21
FOREWORD
UNITS
UNITS
In this manual, the measuring units are indicated with Internatinal System of units (SI).
As for reference, conventionally used Gravitational System of units are indicated in parentheses {
}.
Example:
N {kg}
Nm {kgm}
MPa {kg/cm2}
kPa {mmH2O}
kPa {mmHg}
kW/rpm {HP/rpm}
g/kWh {g/HPh}
00-22
10-04
01
GENERAL
Basic information on air conditioners ....... 01- 2
• Units related to refrigeration ............... 01- 2
Heat ......................................................... 01- 2
Temperature ........................................... 01- 2
Pressure .................................................. 01- 3
Humidity ................................................. 01- 4
• Principle of cooling ............................... 01- 5
• Refrigerants ............................................ 01- 9
• Refrigerator oil ....................................... 01-10
Applicable machine ..................................... 01-14
Specifications ............................................... 01-16
1. Freon gas (R-12) type ............................ 01-16
2. New refrigerant (R134a) type ............... 01-34
fl Refer to the section 40 for the explanation
of New Refrigerant (R134a).
Air conditioner
01-1
1
4
GENERAL
APPLICABLE MACHINE
APPLICABLE MACHINE
1. Freon gas type
Applicable machine model
Manufacturer
Chapter
Bulldozer
DENSO
ZEXEL
DAIKIN
01-14
1
4
10
20
30
D40, 41A-3
D40, 41-5
D50, 53A-17
D50, 53-18
D57S-1
D60, 65A-8
D60, 65-12
D66S-1
D75S-5
D80, 85A-18
D150, 155A-1
D355A-3
D375A-1
D475A-1
—
—
Hydraulic
excavator
Motor grader
PC150-3
GD405A-2
PC200-3
GD505A-2
PC220-2
GD505A-3
PC300-2
GD525A-1
PC300-3
GD605A-2
PC400-1
GD605A-3
PC400-3
GD605A-5
PC650-1, 3, 5
GD625A-1
PC1500-1
GD655A-2
PC100, 120-5, 6 GD705A-2
PC200, 210,
GD705A-3
PC220-6
GD705A-4
PC1000-1
GD805A-1
PC1600-1
GD825A-1
PW150-1
GD825A-2
PW200-1
—
—
—
—
Dump truck
HD325-6
HD465-5
HD785-3
HD1200M-1
HD180-4
HD200-2
HD205-3
HD320, 325-3
HD325-5
HD465-2
HD465-3
HD785-1
HD785-2
HD1200-1
HD1200M-1
HD1600M-1
—
Wheel loader
WA200-1
WA250-3
WA300-1
WA320-3
WA350-1
WA380-3
WA400-1
WA420-3
WA450-1
WA470-3
WA500-1
WA600-1
WA700-1
WA800-2
—
WA200-1
WA300-1
WA350-1
WA400-1
WA450-1
WA500-1
WA600-1
WA800-1
Air conditioner
GENERAL
APPLICABLE
SPECIFlCATIONS
MACHINE
2. New refrigerant type
Applicable machine model
Manufacturer
Chapter
Bulldozer
DENSO
40
ZEXEL
-
TAKAHASHI
WORKS
SANDEN
Air conditioner
D40, 41-5
D50, 53-18
D60, 65-12
D275AX-5
D375A-3
D375A-5
D475A-3
D575A-2
D575A-3
Hydraulic
excavator
PC200-6
PC210-6
PC220-6
PC650-5
PC1000-1
PC1600-1
Motor grader
GD305A-1
GD355A-1
GD405A-2
GD505A-3
GD605A-5
GD705A-4
GD825A-2
Dump truck
HD255-5
HD325-6
HD465-5
HD605-5
HD785-3
HD785-5
HD985-5
HD1200-1
HM400-1
Wheel loader
WA80-3
WA120-3
WA180-3
WA250-3
WA320-3
WA380-3
WA420-3
WA470-3
WA500-1
WA500-3
WA600-1
WA600-3
WA700-1
WA700-3
WA800-2
WA800-3
WA900-3
WA1200-3
HD205-3
50
PC100-6
PC120-6
PC300-5
PC400-5
A57
60
PC27MR-2
PC30MR-2
PC35MR-2
PC40MR-2
PC50MR-2
GD305A-2
GD355A-3
GD405A-3
01-15
(5)
GENERAL
SPECIFlCATIONS
SPECIFlCATIONS
1. FREON GAS (R-12) TYPE
DENSO
Manufacturer
DENSO
D40, 41A-3
D50, 53A-17
D57S-1
D60, 65A-8
D75S-5
Applicable machine
D80, 85A-18
D150, 155A-1
D355A-3
D66S-1
Power source
D375A-1
D475A-1
DC, 24V
Cooling capacity
kcal/h
3,200
3,400
3,200
3,500
Heating capacity
kcal/h
4,800
4,500
4,800
4,500
Compressor
Type
Crank type(2M110B)
Crank type(2M126B)
No. of cylinders-bore x stroke
mm
2-50 x 28
2-50 x 32
Max. speed
rpm
2,200
2,180
cc/rev
110
126
Delivery
Magnet clutch type
Power consumption of clutch
Electromagnetic, dry disc
40
W
Dryer,
receiver Condenser fan
Condenser type
Motor type
Power consumption
Max. air flow
W
m3/min
Plate fin
70F
Cooling by engine fan
125
-
23.3
20.5
424
cc
Evaporator type
475
Plate fin
Blower
Type
Max. air flow
W
m3/min
160
7
6.3
Refrigerant
Refrigerator oil
Amount
Protective equipment
01-16
(5)
7
3-stage selection (H,M, L)
Air mix type
Refrigerating method
Name of refrigerator oil
Corrugated fin
150
Temperature control
Amount
580
Sirocco fan
Air flow control
Name of refrigerant
-
Fusible plug (melting point : 100-105fC/30 kg/cm2),desiccant
Auxiliary equipment
Power consumption of motor
-
ON io OFF
Air flow control
Capacity
Corrugated fin
Vapour (gas) compression refrigerating system
R-12
kg
1.6-2.0
1.5-1.7
DENSO OIL 6 or SUNISO 4 GS
cc
210
300
Fusible plug (receiver)
Air conditioner
GENERAL
SPECIFlCATIONS
DENSO
D40, 41-5
D50, 53-18
D60, 65-12
DC, 24V
2,650 v 265
3,500 v 350
5,300 v 530
-
Crank type(2M110B) Crank type(2M126B)
2-50 x 28
3,000
110
126
Electromagnetic, dry disc
40
Corrugated fin
Plate fin
70F
Cooling by engine fan
Max. 80 v 20%
-
1,100 m3/n v 200
-
Hi io Lo
-
Fusible plug (103fC-110fC)
600
Plate fin
Corrugated fin
Sirocco fan
70
330 v 10% m3/n
180W v 10%
460 v 10%
Hi io Med io Lo
Thermistor type
(ON io OFF)
Reheat type
Vapour (gas) compression refrigerating system
R-12
1.0
ND-Oil 6
210
380
Fusible plug (receiver)
Air conditioner
01-17
(5)
4
GENERAL
SPECIFlCATIONS
Manufacturer
DENSO
PC100, 120-5, 6
PC200, 210, 220-6
PC150-3, PC300-3
PC200-3, PC400-1
PC220-3, PC400-3
PC300-2
PW150-1, PW200-1
Applicable machine
Power source
PC650-1, 3, 5
PC1500-1
PC1000-1
PC1600-1
DC, 24V
Cooling capacity
kcal/h
2,800
3,200
Heating capacity
kcal/h
3,100
4,800
Compressor
Type
Crank type(2M110B)
No. of cylinders-bore x stroke
mm
Max. speed
rpm
Delivery
110
40
W
Aluminium tube, corrugated fin
Motor type
Power consumption
Max. air flow
70F
W
80
125
m3/min
15
20.5
ON io OFF
Air flow control
Fusible plug (melting point : 100-105fC/
30 kg/cm2), desiccant
Auxiliary equipment
Capacity
cc
Evaporator type
525
475
Corrugated fin
Plate fin
Blower
Type
Power consumption of motor
Max. air flow
Sirocco fan
W
150
160
m3/min
5.5
6.3
Air flow control
3-stage selection (H,M, L)
Temperature control
Air mix type
Refrigerant
Name of refrigerant
Refrigerator oil
Refrigerating method
Name of refrigerator oil
Amount
Amount
Protective equipment
01-18
(5)
2,200
Electromagnetic, dry disc
Condenser type
Dryer,
receiver Condenser fan
2,500-3,100
cc/rev
Magnet clutch type
Power consumption of clutch
2-50 x 28
Vapour (gas) compression refrigerating system
R-12
kg
1.2
1.6-2.0
DENSO OIL 6 or SUNISO 4 GS
cc
280
210
Fusible plug (receiver)
Air conditioner
GENERAL
SPECIFlCATIONS
DENSO
WA200-1
WA250-3
WA300-1
WA320-3
WA350-1
WA380-3
WA400-1
WA420-3
WA450-1
WA470-3
WA500-1
WA600-1
WA700-1
WA800-2
DC, 24V
3,500
4,000
Crank type(2M126B)
2-50 x 32
126
Electromagnetic, dry disc
40
Copper tube 4 lines plate fin
86F
160
23.3
ON io OFF
Fusible plug (melting point : 100-105fC/30 kg/cm2), desiccant
580
Aluminium tube, corrugated fin
Sirocco fan
150
Cooling: 7 (Heating: 5.3)
3-stage selection (H,M, L)
Air mix type
Vapour (gas) compression refrigerating system
R-12
1.5-1.6
1.6-1.7
1.5-1.6
DENSO OIL 6 or SUNISO 4 GS
380
Fusible plug (receiver), pressure switch (air conditioner unit)
Air conditioner
01-19
(5)
4
GENERAL
SPECIFlCATIONS
Manufacturer
DENSO
Applicable machine
GD405A-2
GD505A-2
GD605A-3
GD655A-3
GD705A-3
GD705A-4
Power source
GD605A-2
GD655A-2
GD705A-2
GD505A-3
GD525A-1
DC, 24V
Cooling capacity
kcal/h
2,800
2,300
Heating capacity
kcal/h
3,200
3,100
Compressor
Type
Crank type(2M110B)
No. of cylinders-bore x stroke
mm
Max. speed
rpm
Delivery
2-50 x 28
2,196
40
W
Dryer,
receiver Condenser fan
Aluminium tube, corrugated fin
Motor type
Max. air flow
70F
W
80
125
80
125
m3/min
15
23.3
15
23.3
ON io OFF
Air flow control
Fusible plug (melting point : 100-105fC/30 kg/cm2), desiccant
Auxiliary equipment
Capacity
580
cc
Evaporator type
Corrugated fin
Type
Blower
Power consumption of motor
Max. air flow
Sirocco fan
W
110
80
110
m3/min
5.5
4.3
5.5
3-stage selection
2-stage selection 3-stage selection 2-stage selection
(H,M, L)
Air flow control
Temperature control
Air mix type
Refrigerant
Refrigerator oil
Refrigerating method
Name of refrigerant
Name of refrigerator oil
Amount
Amount
Protective equipment
01-20
(5)
2,455
Electromagnetic, dry disc
Condenser type
Power consumption
2,057
110
cc/rev
Magnet clutch type
Power consumption of clutch
2,470
Vapour (gas) compression refrigerating system
R-12
kg
1.6
1.2
1.6
1.2
DENSO OIL 6 or SUNISO 4 GS
cc
210
Fusible plug (receiver)
Air conditioner
GENERAL
SPECIFlCATIONS
DENSO
GD805A-1
GD825A-1
GD605A-5
GD825A-2
DC, 24V
2,800
3,800
3,200
4,000
Crank type(2M110B)
-
2-50 x 28
2-50 x 32
1,706
1,589
6,000
110
126
Electromagnetic, dry disc
40
Aluminium tube, corrugated fin
70F
Cooling by engine fan
80
-
15
-
ON io OFF
100-105fC/30 kg/cm2
580
600
Corrugated fin
-
Sirocco fan
110
-
5.5
7
3-stage selection
Air mix type
Vapour (gas) compression refrigerating system
R-12
1.6
1.6-2.0
DENSO OIL 6 or
SUNISO 4 GS
1.6
DENSO OIL 6
210
300
Fusible plug (receiver)
Air conditioner
01-21
(5)
4
GENERAL
SPECIFlCATIONS
BOSCH (ZEXEL)
Manufacturer
BOSCH (ZEXEL)
Applicable machine
HD180-4, HD200-2, HD205-3 (• - #2084), HD320, 325-3, HD325-5,
HD465-2, HD465-3, HD785-1, HD785-2, HD1200-1, HD1200M-1,
HD1600M-1
Power source
DC, 24V
Cooling capacity
kcal/h
3,100
Heating capacity
kcal/h
3,200
Compressor
Type
Crank type
No. of cylinders-bore x stroke
mm
2-48 x 34
Max. speed
rpm
-
Delivery
cc/rev
Magnet clutch type
Power consumption of clutch
Electromagnetic, dry disc
W
Dryer,
receiver Condenser fan
Condenser type
Max. air flow
Forced cooling by engine fan
W
-
m3/min
-
Air flow control
Fusible plug (melting point : 105fC/30 kg/cm2)
Auxiliary equipment
Capacity
cc
Evaporator type
Blower
Max. air flow
Sirocco fan
W
180
m3/min
450
Air flow control
3-stage selection (H,M, L)
Temperature control
Reheat air mix type
Refrig- Refrigerator oil erant
Refrigerating method
Vapour (gas) compression refrigerating system
Name of refrigerant
Amount
R-12
kg
Protective equipment
1.2
SUNISO 351 or SUNISO 5 GS
Name of refrigerator oil
Amount
500
Aluminium tube, aluminium fin
Type
Power consumption of motor
Max. 30
Corrugated fin
Motor type
Power consumption
123
cc
300
Fusible plug (receiver), pressure switch (*1)
*1. Pressure switch: OFF at max. 0.2 MPa {2 kg/cm2}, OFF at min. 2.7 {27 kg/cm2}
01-24
01-22
(5)
Air conditioner
GENERAL
Air conditioner
SPECIFlCATIONS
01-23
(5)
GENERAL
SPECIFlCATIONS
DAIKIN
Manufacturer
DAIKIN
(TXF40A1)
WA350-1
WA400-1
Applicable machine
Power source
(TXF40A2)
WA200-1
WA300-1
(TXF40A3)
WA600-1
WA800-1
DC, 24V (22V - 30V)
Cooling capacity
kcal/h
3,900
Heating capacity
kcal/h
4,000
Compressor
Type
Vane rotary type (TXC40A, SS170P)
No. of cylinders-bore x stroke
mm
-
Max. speed
rpm
2,000
cc/rev
121
Delivery
Magnet clutch type
Power consumption of clutch
Electromagnetic, dry disc
W
Dryer,
receiver Condenser fan
Condenser type
-
Power consumption
W
Max. air flow
3
m /min
Air flow control
cc
Blower
Sirocco fan
W
160
m3/min
6.7
Air flow control
3-stage selection (H,M, L)
Temperature control
Air mix type (frost thermo)
Refrig- Refrigerator oil erant
Refrigerating method
R-12 (DF-12)
kg
01-28
01-24
1.3
Daphene 7963
Name of refrigerator oil
Protective equipment
(5)
Vapour (gas) compression refrigerating system
Name of refrigerant
Amount
-
Corrugated fin
Type
Amount
35
Fusible plug (melting point : 100-107fC/30 kg/cm2), desiccant
Evaporator type
Max. air flow
190
-
Auxiliary equipment
Power consumption of motor
Max. 40
Aluminium tube, corrugated fin
Motor type
Capacity
(TXF40A4)
WA450-1
WA500-1
cc
220
Fusible plug, pressure switch (receiver), temperature fuse (resistor), thermo protector (compressor)
Air conditioner
GENERAL
Air conditioner
SPECIFlCATIONS
01-33
(5)
GENERAL
SPECIFlCATIONS
2. NEW REFRIGERANT (R134a) TYPE
DENSO
Manufacturer
DENSO
D40, 41-5
D50, 53-18
Applicable machine
Power source
Cooling capacity
kcal/h
2,650 v 265
Heating capacity
kcal/h
-
Compressor
Type
Dryer,
receiver Condenser fan
3,400 v 340
4,300 v 430
4,400 v 440
5,400 v 540
mm
10 x 29.5 x 22.7
Max. speed
rpm
3,000
cc/rev
155
Delivery
Magnet clutch type
Electromagnetic, dry disc
Max. air flow
40
W
Motor type
Power consumption
W
m3/min
Corrugated fin
Plate fin
70F
Cooling by engine fan
Max. 80 v 20%
1,100m3/n v 200
Hi io Lo
Air flow control
250 v 25
-
500 v 50
-
Auxiliary equipment
Capacity
370
cc
Evaporator type
Plate fin
Corrugated fin
Type
Power consumption of motor
Max. air flow
Sirocco fan
W
m3/min
70
350 v 10% m3/n
Refrigerant
Refrigerator oil
Refrigerating method
Name of refrigerator oil
Amount
Protective equipment
01-34
460 v 10%
500 v 10%
Thermistor type
(ON io OFF)
Temperature control
Amount
180W v 10%
Hi io Med io Lo
Air flow control
Name of refrigerant
D475A-3
Swash plate type(10PA15C)
Condenser type
Blower
DC, 24V
No. of cylinders-bore x stroke
Power consumption of clutch
(5)
D375A-3
D60, 65-12
Reheat type
Vapour (gas) compression refrigerating system
R134a
kg
1.0
ND-Oil 8
cc
180
Pressure relief valve (compressor)
Air conditioner
GENERAL
SPECIFlCATIONS
DENSO
D275AX-5
D575A-3
3,500 v 350
D375A-5
DC, 24V
4,300 v 430
4,500 v 450
5,400 v 540
Swash plate type(10PA15C)
10 x 29.5 x 22.7
3,000
155
Electromagnetic, dry disc
40
Corrugated fin
Cool: 160 v 16
Hot: 150 v 15
Plate fin
Cooling by engine fan
500 v 50
250 v 25
370
550
Corrugated fin
Sirocco fan
180W v 10%
500 v 10
Hi io Med io Lo
Reheat type
Vapour (gas) compression refrigerating system
R134a
1.0
ND-Oil 8
180
Pressure relief valve Pressure relief valve (compressor)
Air conditioner
01-35
(5)
4
GENERAL
SPECIFlCATIONS
Manufacturer
DENSO
PC200-6
PC210-6
Applicable machine
PC220-6
Power source
PC650-5
PC1000-1
DC, 24V
Cooling capacity
kcal/h
3,300
3,200
2,800
Heating capacity
kcal/h
3,700
3,500
3,100
Compressor
Type
Swash plate type(10PA15C)
No. of cylinders-bore x stroke
mm
Max. speed
rpm
Delivery
10 x 29.5 x 22.7
2,000
2,400
155.3
cc/rev
Magnet clutch type
Power consumption of clutch
Electromagnetic, dry disc
40
W
Dryer,
receiver Condenser fan
Condenser type
Corrugated fin
Cooling by engine fan
-
Cooling by engine fan
-
W
-
120
-
80
m3/min
-
30
-
15
-
ON io OFF
-
ON io OFF
Motor type
Power consumption
Max. air flow
Air flow control
Desiccant
Auxiliary equipment
Capacity
550
cc
Evaporator type
Corrugated fin
-
Type
Blower
Power consumption of motor
Max. air flow
W
170
m3/min
420
360
Air mix type
Refrigerant
Refrigerator oil
Refrigerating method
Name of refrigerator oil
Amount
Amount
Protective equipment
01-36
330
3-stage selection
Temperature control
(5)
150
Air flow control
Name of refrigerant
2,100
Thermostat type
Vapour (gas) compression refrigerating system
R134
kg
1.00-1.14
0.98-1.12
DENSO OIL 8
cc
180
220
Receiver
Air conditioner
GENERAL
SPECIFlCATIONS
DENSO
PC1600-1
DC, 24V
3,500
4,500
Swash plate
type(10PA15C)
10 x 29.5 x 22.7
2,400
155.3
Electromagnetic,
dry disc
40
Corrugated fin
Cooling by engine fan
550
Corrugated fin
130
420
3-stage selection
Thermostat type
Vapour (gas) compression refrigerating system
R134a
1.38-1.52
DENSO OIL 8
180
Receiver
Air conditioner
01-37
(5)
4
GENERAL
SPECIFlCATIONS
Manufacturer
DENSO
WA120-3
WA180-3
WA250-3
WA320-3
WA380-3
WA420-3
WA470-3
Applicable machine
Power source
WA500-1
WA600-1
WA700-1
WA800-2
DC, 24V
Cooling capacity
kcal/h
4,000
3,800
Heating capacity
kcal/h
5,100
4,000
Compressor
Type
Swash plate type
No. of cylinders-bore x stroke
mm
30 x 22
Max. speed
rpm
3,000
Delivery
cc/rev
155
Magnet clutch type
Power consumption of clutch
Rubber hub
Max. 40
W
Dryer,
receiver Condenser fan
Condenser type
Serpentine type
Motor type
Power consumption
Max. air flow
Ferrite (o 70)
W
110
m3/min
18
Air flow control
2-stage (Hi/Lo)
Auxiliary equipment
With sight glass
Capacity
370
cc
Evaporator type
Single tank
Type
Blower
Power consumption of motor
Max. air flow
Ferrite (o 86)
W
(Cooler) 225,
(Heater) 215
Max. 480
m3/min
9
7
4-stage selection
(Hi/Mez//Mel/Lo)
3-stage selection
(Hi/Me/Lo)
Air flow control
Temperature control
Air mix type
Refrigerant
Refrigerator oil
Refrigerating method
Name of refrigerant
Name of refrigerator oil
Amount
Amount
Protective equipment
01-38
(5)
Serpentine
Expansion
R134a
kg
1.3-1.5
ND-OIL 8
cc
180
Pressure switch relief valve
Air conditioner
GENERAL
SPECIFlCATIONS
DENSO
WA100-3
WA150-3
WA200-3
WA250-3
WA80-3
WA300-3, WA380-3,
WA420-3, WA470-3,
WA500-3, WA600-3,
WA700-3, WA800-3,
WA900-3
WA1200-3
DC, 24V
3,000
4,000
4,300
4,600
5,000
Swash plate type
(10P08E)
Swash plate type (10PA15C)
10-25 x 16.9
10-29.5 x 22.7
6,000
82.9
155.3
Electromagnetic,
dry disc (S25)
Electromagnetic, dry disc (L50)
Max. 35
Max. 40
Corrugated fin
Ferrite motor
80
19
120 x 2
80 x 2
18 x 2
19 x 2
26.7
2-stage (Hi/Lo)
550
Aluminium tube, aluminium fin
Sirocco fan
225
9
4-stage selection (Hi/Mz//Ml/Lo)
Reheat type
Vapour (gas) compression refrigerating system
R134a
1.05
1.25
1.40
DENSO OIL 8
120-135
220-235
Pressure switch (*1)
*1. Pressure switch: OFF at max. 0.2 MPa {2 kg/cm2}, OFF at min. 2.7 {27 kg/cm2}
Air conditioner
01-39
(5)
GENERAL
SPECIFlCATIONS
Manufacturer
DENSO
GD705A-4
GD605A-5
GD505A-3
GD405A-2
GD355A-1
GD305A-1
GD825A-2
GD505A-3A
Applicable machine
Power source
DC, 24V
Cooling capacity
kcal/h
4,000
Heating capacity
kcal/h
5,100
Compressor
Type
Swash plate type (10PA15C)
No. of cylinders-bore x stroke
mm
10 x 29.5 x 22.7
Max. speed
rpm
6,000
cc/rev
126
Delivery
Magnet clutch type
Power consumption of clutch
Electromagnetic, dry disc (L50)
Dryer,
receiver Condenser fan
Condenser type
Aluminium tube, aluminium fin
Motor type
Power consumption
Max. air flow
40
W
Cooling by engine fan
-
W
-
132
m3/min
-
18
-
ON io OFF
Air flow control
Auxiliary equipment
Capacity
-
550
cc
Evaporator type
-
Blower
Type
Power consumption of motor
Max. air flow
Sirocco fan
W
225
3
9.2
m /min
Air flow control
4-stage selection
Temperature control
Air mix type
Refrig- Refrigerator oil erant
Refrigerating method
Name of refrigerant
Amount
R134a
kg
Amount
01-40
1.6
-
DENSO OIL 8
Name of refrigerator oil
Protective equipment
(5)
Gas compression refrigerating system
cc
180
-
Air conditioner
GENERAL
SPECIFlCATIONS
DENSO
HD325-6 #5267HD405-6 • - #1054
HD465-5 #4192 HD605-5 • - #1012 HD785-3 #2269 HD985-5 • - #1020
HD1200-1 #1848 -
HD255-5
HM400-1
HD325-6 #5680 HD405-6 #1055 HD465-5 #4626 HD605-5 #1013 HD785-5 #4001 HD985-5 #1021 -
DC, 24V
3,200
4,000
3,500
5,100
Swash plate type (10PA15C)
Swash plate type
(10S15C)
Swash plate type
(10PA15C)
10-29.5 x 22.7
10-32 x 20.8
10-29.5 x 22.7
6,000
155.3
157.3
155.3
Electromagnetic, dry disc
Electromagnetic,
dry disc (L50T)
Electromagnetic,
dry disc (L50)
Max. 40
Corrugated fin
Forced cooling by
engine fan
-
-
-
-
-
-
-
Fusible plug (melting
point : 105fC/30 kg/cm2)
550
Aluminium tube, aluminium fin
Sirocco fan
150
225
360
550
3-stage selection
(H, M, L)
4-stage selection (H, Mz, Ml, L)
Reheat type
Vapour (gas) compression refrigerating system
R134a
1.1
DENSO OIL 8
180
220-235
Pressure switch (*1)
*1. Pressure switch: OFF at max. 0.2 MPa {2 kg/cm2}, OFF at min. 3.1 {32 kg/cm2}
Air conditioner
01-41
(5)
GENERAL
SPECIFlCATIONS
ZEXEL
Manufacturer
ZEXEL
Applicable machine
HD205-3 (#2085 -)
Power source
DC, 24V
Cooling capacity
kcal/h
3,100
Heating capacity
kcal/h
3,200
Compressor
Type
Swash plate type
No. of cylinders-bore x stroke
mm
6-37 x 25.8
Max. speed
rpm
7,000
cc/rev
167
Delivery
Magnet clutch type
Power consumption of clutch
Dryer,
receiver Condenser fan
Condenser
Electromagnetic, dry disc
W
Type
Heat dissipation
Corrugated fin type
kW
Motor type
Power consumption
Max. air flow
W
-
m3/min
Fusible plug (melting point : 105fC/30 kg/cm2)
Auxiliary equipment
cc
Evaporator type
Blower
Max. air flow
Sirocco fan
W
180
m3/min
450
Air flow control
3-stage selection (H,M, L)
Temperature control
Reheat air mix type
Vapour (gas) compression refrigerating system
Refrig- Refrigerator oil erant
Refrigerating method
Name of refrigerant
Amount
R134a
kg
Name of refrigerator oil
Amount
Protective equipment
500
Aluminium tube, aluminium fin
Type
Power consumption of motor
Forced cooling by engine fan
Air flow control
Capacity
Max. 45
1.1
ZXL100PG
cc
300
Fusible plug (receiver), pressure switch(*1)
*1. Pressure switch: OFF at max. 0.2 MPa {2 kg/cm2}, OFF at min. 3.1 {32 kg/cm2}
01-42
01-44
(5)
(6)
Air conditioner
GENERAL
SPECIFlCATIONS
Manufacturer
ZEXEL
PC78US-6
PC78UU-6
Applicable machine
Power source
PC128US-2
PC138US-2
DC, 12V
Cooling capacity
kW
5 (Air flow: 450m3/h)
Heating capacity
kW
4.65 (Air flow: 400m3/h)
Compressor
Type
Swash plate (DKS15CH), piston type
No. of cylinders-bore x stroke
mm
6-36 x 24
Max. speed
rpm
7,000
cc/rev
147
Delivery
Magnet clutch type
Power consumption of clutch
Dryer, Condenser fan
receiver
Condenser
Electromagnetic, dry disc
Type
Heat dissipation
45
W
kW
Parallel flow type
Sub cool type
8.13 (at 5 m/s)
7.93 (at 5 m/s)
Motor type
Power consumption
Max. air flow
Cooling by engine fan
W
-
m3/min
-
Air flow control
-
Auxiliary equipment
Capacity
cc
Desiccant 150g
Desiccant 100g
400
190
Evaporator type
Plate fin
Blower
Type
Power consumption of motor
Max. air flow
Sirocco fan
W
153
3
400
m /h
Air flow control
4-stage selection, automatic
Temperature control
8-stage selection, automatic
Refrig- Refrigerator oil erant
Refrigerating method
Vapour (gas) compression refrigerating system
Name of refrigerant
Amount
R134a
kg
Name of refrigerator oil
Amount
Protective equipment
Air conditioner
0.9 ± 0.05
0.7 ± 0.05
ZXL100PG
cc
Compressor: 210, Receiver dryer (tank): 50
Pressure switch
01-45
(6)
GENERAL
Air conditioner
SPECIFlCATIONS
01-43
(5)
GENERAL
SPECIFlCATIONS
TAKAHASHI WORKS
Manufacturer
TAKAHASHI WORKS
A57
GD305A-3
GD355A-3
GD405A-3
Vane rotary type
Rotary type
(SS-990)
Elliptical type,
Vane rotary
-
(No. of vanes : 5)
PC100-6
PC120-6
Applicable machine
PC300-5
PC400-5
Power source
DC, 24V
Cooling capacity
kcal/h
Heating capacity
kcal/h
3,300
4,000
Compressor
Type
No. of cylinders-bore x stroke
mm
Max. speed
rpm
Delivery
Aluminium tube,
corrugated fin
Corrugated fin
Aluminium tube,
corrugated fin
Cooling by engine fan
-
Cooling by engine fan
W
-
160
-
m3/min
-
24
-
-
ON io OFF
-
100-105fC/30 kgm
Desiccant
Desiccant 300 g
600
780
780
Dryer,
receiver Condenser fan
cc
Evaporator type
Serpentine
Blower
Type
Max. air flow
W
Refrigerant
Refrigerator oil
Amount
Protective equipment
01-50
01-44
(5)
-
Sirocco fan
-
190
-
6.7
Air mix type
Refrigerating method
Name of refrigerator oil
Sirocco fan
selection
3-stage selection 3-stage selection 3-stage
(H, M, L)
Temperature control
Amount
Corrugated fin
m3/min
Air flow control
Name of refrigerant
Electromagnetic,
dry disc
40 (DC, 24V, 20fC)
Auxiliary equipment
Power consumption of motor
99
40
Air flow control
Capacity
6,500
42.3
W
Motor type
Max. air flow
2,000
Dry single plate type Electromagnetic
Condenser type
Power consumption
6,500
cc/rev
Magnet clutch type
Power consumption of clutch
3,700
Electronic thermo Electronic thermo
Vapour (gas) compression refrigerating system
R134a
kg
0.8
0.95-1.09
(Estimated calculation value : 1.1)
PAG SK20
SK08
Idemitsu [DH-PR] (compressor maker nominal SK20)
220
cc
Receiver
Pressure switch (air conditioner
unit), thermal switch (compressor) relief valve (compressor)
Air conditioner
GENERAL
Air conditioner
SPECIFlCATIONS
01-45
(5)
GENERAL
SPECIFlCATIONS
SANDEN
Manufacturer
SANDEN
PC27MR-2
PC30MR-2
PC35MR-2
PC40MR-2
PC50MR-2
Applicable machine
Power source
DC, 12V
Cooling capacity
kcal/h
3,500
Heating capacity
kcal/h
3,500
Compressor
Type
Swash plate type
No. of cylinders-bore x stroke
mm
7 x 25.4 x 28.1
Max. speed
rpm
9,300
cc/rev
99.8
Delivery
Magnet clutch type
Power consumption of clutch
Electromagnetic, dry disc
W
Dryer,
receiver Condenser fan
Condenser type
Plate fin
Motor type
Power consumption
Max. air flow
Cooling by engine fan
W
-
m3/min
-
Air flow control
-
Auxiliary equipment
Capacity
Desiccant 100g
cc
Evaporator type
Blower
Max. air flow
Sirocco fan
W
120
m3/min
6.7
Air flow control
3-stage selection (H,M, L)
Temperature control
Electronic thermostat type
Refrig- Refrigerator oil erant
Refrigerating method
Vapour (gas) compression refrigerating system
Name of refrigerant
Amount
R134a
kg
Amount
01-60
01-46
0.6-0.7
SP10A
Name of refrigerator oil
Protective equipment
(5)
240
Plate fin
Type
Power consumption of motor
43
cc
100
Pressure switch
Air conditioner
STRUCTURE AND FUNCTION
STRUCTURE AND FUNCTION
DENSO (FREON GAS TYPE)
Piping diagram............................................................................................................................................11- 2
Electric wiring diagram ...............................................................................................................................11- 3
Compressor ................................................................................................................................................11- 4
Magnetic clutch...........................................................................................................................................11- 7
Condenser ..................................................................................................................................................11- 8
Receiver .....................................................................................................................................................11- 10
Air conditioner unit......................................................................................................................................11- 12
1. Expansion valve .....................................................................................................................................11- 13
2. Evaporator ..............................................................................................................................................11- 15
3. Thermostat .............................................................................................................................................11- 15
4. Pressure switch ......................................................................................................................................11- 16
5. Heater.....................................................................................................................................................11- 18
6. Blower unit..............................................................................................................................................11- 18
7. Piping......................................................................................................................................................11- 19
8. Air control system ...................................................................................................................................11- 20
Names and functions..................................................................................................................................11- 21
Operation....................................................................................................................................................11- 22
Air conditioner
11-1
(5)
(5)
TROUBLESHOOTING
TESTING AND ADJUSTING
DENSO (FREON GAS TYPE)
Service tool................................................................................................................................................ 12- 2
1. Gauge manifold ..................................................................................................................................... 12- 2
2. Gas leak detector .................................................................................................................................. 12- 5
3. Valve for service cans............................................................................................................................ 12- 8
Maintenance procedure............................................................................................................................. 12- 9
Troubleshooting ......................................................................................................................................... 12- 23
1. Defective heating .................................................................................................................................. 12- 24
2. Troubleshooting table ............................................................................................................................ 12- 25
3. Defective heating................................................................................................................................... 12- 27
4. Troubleshooting using gauge manifold.................................................................................................. 12- 28
Air conditioner
12-1
(5)
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY AND ASSEMBLY
DENSO (FREON GAS TYPE)
Special tools .............................................................................................................................................. 13- 2
Disassembly of magnetic clutch ................................................................................................................ 13- 3
Assembly of magnetic clutch ..................................................................................................................... 13- 7
Disassembly of air conditioner unit............................................................................................................ 13- 9
Disassembly of blower unit........................................................................................................................ 13- 20
Disassembly of condenser ........................................................................................................................ 13- 22
Air conditioner
13-1
(5)
STRUCTURE AND FUNCTION
STRUCTURE AND FUNCTION
ZEXEL (DIESEL KIKI)
Location of unit .......................................................................................................................................... 21- 2
Electrical circuit diagram............................................................................................................................ 21- 3
Piping diagram........................................................................................................................................... 21- 4
Compressor ............................................................................................................................................... 21- 5
Magnetic clutch.......................................................................................................................................... 21- 7
Condenser ................................................................................................................................................. 21- 8
Receiver (liquid tank)................................................................................................................................. 21- 9
Expansion valve ........................................................................................................................................ 21- 10
Evaporator ................................................................................................................................................. 21- 12
Air conditioner
21-1
(5)
(5)
TROUBLESHOOTING
TESTING AND ADJUSTING
ZEXEL (DIESEL KIKI)
Tightening torque tables ............................................................................................................................ 22- 2
Special tools .............................................................................................................................................. 22- 4
Service procedure ..................................................................................................................................... 22- 12
Inspection and maintenance...................................................................................................................... 22- 23
Troubleshooting ......................................................................................................................................... 22- 32
Air conditioner
22-1
(5)
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY AND ASSEMBLY
ZEXEL (DIESEL KIKI)
Special tools .............................................................................................................................................. 23- 2
Disassembly of compressor assembly ...................................................................................................... 23- 3
Judging defective locations when disassembling ...................................................................................... 23- 6
Disassembly .............................................................................................................................................. 23- 8
Assembly ................................................................................................................................................... 23- 12
Air conditioner
23-1
(5)
STRUCTURE AND FUNCTION
STRUCTURE AND FUNCTION
DAIKIN
Piping diagram........................................................................................................................................... 31- 2
Electrical circuit diagram............................................................................................................................ 31- 3
Compressor (Rotary type) ......................................................................................................................... 31- 4
Condenser ................................................................................................................................................. 31- 6
Receiver dryer ........................................................................................................................................... 31- 8
Air conditioner unit..................................................................................................................................... 31- 9
Operating procedure.................................................................................................................................. 31- 13
Air conditioner
31-1
(5)
(5)
TROUBLESHOOTING
TESTING AND ADJUSTING
DAIKIN
Service tools .............................................................................................................................................. 32- 2
Service procedure ..................................................................................................................................... 32- 6
In-season checks....................................................................................................................................... 32- 13
Off-season checks ..................................................................................................................................... 32- 13
Using air compressor dipstick.................................................................................................................... 32- 15
Troubleshooting ......................................................................................................................................... 32- 16
Electric system functional sequence..................................................................................................... 32- 16
Defective cooling................................................................................................................................... 32- 17
Air conditioner
32-1
(5)
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY AND ASSEMBLY
DAIKIN
Tools .......................................................................................................................................................... 33- 2
Disassembly of compressor ...................................................................................................................... 33- 5
Assembly of compressor ........................................................................................................................... 33- 8
Disassembly and testing of air conditioner unit ..........................................................................................33- 11
Condenser unit .......................................................................................................................................... 33- 20
Receiver dryer ........................................................................................................................................... 33- 20
Air conditioner
33-1
(5)
STRUCTURE AND FUNCTION
STRUCTURE AND FUNCTION
DENSO (NEW REFRIGERANT TYPE)
Fundamentals of air conditioning
1. Principle of air conditioning.................................................................................................................... 41- 2
2. Basic refrigerating cycle ........................................................................................................................ 41- 3
3. Refrigerant............................................................................................................................................. 41- 6
4. Refrigerating cycle of air conditioner ..................................................................................................... 41- 8
Configuration of refrigerating cycle
1. Structure of each refrigerating cycle part............................................................................................... 41- 10
2. Compressor ........................................................................................................................................... 41- 12
3. Magnetic clutch...................................................................................................................................... 41- 16
4. Condenser ............................................................................................................................................. 41- 17
5. Receiver tank......................................................................................................................................... 41- 17
6. Expansion valve .................................................................................................................................... 41- 18
7. Evaporator ............................................................................................................................................. 41- 21
8. Sight glass ............................................................................................................................................. 41- 22
Control system
1. Outline of control ................................................................................................................................... 41- 23
2. Temperature control............................................................................................................................... 41- 24
3. Air flow control ....................................................................................................................................... 41- 25
4. Circulated air and fresh air selection ..................................................................................................... 41- 26
5. Defrosting control .................................................................................................................................. 41- 26
6. Compressor control ............................................................................................................................... 41- 27
Air conditioner
41-1
(5)
(5)
STRUCTURE AND FUNCTION
FUNDAMENTALS OF AIR CONDITIONING
FUNDAMENTALS OF AIR
CONDITIONING
Alcohol
evaporates.
1. Principle of air conditioning
If alcohol is applied to your skin, you feel cold. If
you sprinkle water over your garden in summer,
you feel cool. The cause of these phenomena is that
alcohol and water absorb heat (which is called latent heat) from material around them when they
evaporate. That is, a liquid (such as alcohol, water,
etc.) needs heat (heat of vaporization) to change to
a gas (alcohol vapor, steam, etc.) and the material
from which heat is absorbed (the material in contact with the liquid) is cooled.
These natural phenomena directly show the principle of air conditioning. Coolness and coldness are
obtained by utilizing these phenomena. If the vapor
of the liquid used for air conditioning is discharged
into the atmosphere, however, the liquid must be
supplied constantly, and that is not practical. Accordingly, the vapor is cooled to be liquefied again
and circulated.
To liquefy a gas, it must be cooled first. If it is
compressed at this time, it is liquefied more easily.
Then, a compressor and a condenser are used to
compress and cool the gas.
41-2
4
Heat
Sanitary cotton
soaked in alcohol
(Liquid absorbs heat from material around it)
Evaporation
Gas
Liquid
Condensation
(Heat of gas is radiated)
Air conditioner
STRUCTURE AND FUNCTION
FUNDAMENTALS OF AIR CONDITIONING
2. Basic refrigerating cycle
2.1 Configuration
Generally, an air conditioner means equipment which circulates a volatile liquid (called a refrigerant)
in a sealed pipe circuit and evaporates and liquefies it repeatedly during circulation.
The basic components of this equipment are as follows.
• Evaporator
The refrigerant evaporates in the evaporator to absorb heats from around the pipe and cool the room.
• Compressor
The compressor compresses the refrigerant gas evaporated in the evaporator so that the gas will be
liquefied easily in the condenser.
• Condenser
The condenser cools and liquefies the high-temperature and high-pressure refrigerant gas compressed
with the compressor.
• Expansion valve
The expansion valve is a kind of a choke valve, which keeps the pressure in the evaporator low. That
is, the high-pressure refrigerant liquid is spouted through a narrow gap into the evaporator, where it
becomes low-pressure and low-temperature mist and evaporates rapidly.
Heat is absorbed from
material around evaporator.
Expansion valve
Evaporator
Compressor
Condenser
Heat is radiated.
Air conditioner
41-3
4
STRUCTURE AND FUNCTION
FUNDAMENTALS OF AIR CONDITIONING
2.2 Good condition for air conditioner
The first good condition for an air conditioner is that the refrigerant evaporates at low temperature
and liquefies easily and it evaporates much in the evaporator.
Heat is absorbed.
Expansion valve
Low
pressure High
pressure
Liquid
Mist
Gas
Evaporator
Compressor
Condenser
Heat is radiated.
The condition of the refrigerant in the refrigerating cycle is as follows.
1 The refrigerant compressed in the compressor is high-temperature and high-pressure gas.
2 As the refrigerant passes through the condenser, it is cooled and liquefied. It must be liquefied
completely at the outlet of the condenser. If the refrigerant is not cooled sufficiently in the
condenser, some of it is still gas at the outlet of the condenser and the refrigerating capacity is
lowered.
3 After the liquefied refrigerant passes the expansion valve, it becomes mist. The expansion valve is
called the choke valve, too. The high-pressure refrigerant liquid is spouted through a small hole so
that it will evaporate easily.
4 In the evaporator, the refrigerant mist evaporates rapidly and absorbs the heat inside the cab. The
refrigerant gasifies completely near the outlet of the evaporator.
41-4
4
Air conditioner
STRUCTURE AND FUNCTION
FUNDAMENTALS OF AIR CONDITIONING
If the refrigerant is insufficient, all of it vaporizes before it reaches the evaporator outlet and the
evaporator capacity lowers. If the refrigerant is too much, on the other hand, all of it does not vaporize
in the evaporator and flows in the compressor in the form of liquid and the compressor may be broken
since it compresses the liquid. Accordingly, the quantity of the refrigerant must be controlled according to various conditions.
The air conditioner does not only lower the indoor temperature but lowers the indoor humidity to keep
the environment fresh. That is, if the warm indoor air passes through the evaporator, it is cooled and
its moisture is condensed into water drops on the evaporator fins. As a result, the moisture in the air
is removed and the humidity is lowered. The water drops on the fins are discharged out of the
machine through a hose.
[Reference]
• Condensation
If a glass containing iced water is left in the atmosphere, water drops are formed on the glass surface. This phenomenon shows that the steam in the
air (the vaporized water which the air always contains) is cooled and condensed by the iced water in
the glass. (The iced water is warmed by the heat of
condensation.)
Air conditioner
41-5
4
STRUCTURE AND FUNCTION
FUNDAMENTALS OF AIR CONDITIONING
3. Refrigerant
A material which circulates in a refrigerating cycle to transfer heat is called the refrigerant.
In air conditioners, HFC134a (R134a) which is a kind of Freon and which contains no chlorine is used.
3.1 Characteristics of refrigerant
The characteristics of HFC134a (R134a) are shown in the following figure.
Refrigerant temperature (°C)
Gas
Liquefied if
cooled by
this
temperature
Liquid
Gauge pressure
As indicated by the above curve, the refrigerant under high pressure is liquid up to a relatively high
temperature. Under low pressure, however, the refrigerant vaporizes at 0°C or even at –10°C.
If the refrigerant vaporizes at 0°C, the evaporator is also at 0°C. The air passes through the evaporator
is cooled consequently. If the pressure is lowered to a state where the refrigerant vaporizes at –5°C,
the evaporator is kept at –5°C. As a result, the surface of the evaporator is frosted and air does not flow
well and the refrigerating performance is lowered.
The gasified refrigerant must be liquefied. Considering the environment of the condenser on a construction machinery in summer, it is impossible to keep the condenser temperature as low as 40°C. If
the condenser temperature can be kept as low as about 60°C, HFC134a is liquefied under pressure of
about 1.7 MPa {about 17 kg/cm2}. In addition, if the refrigerant gas is compressed to 1.7 MPa (with the
compressor), its temperature rises to about 80°C. That is, the above curve shows the following; The
refrigerant gas is heated to about 80°C at the condenser inlet. If it is cooled by about 20°C at the
condenser outlet, however, it becomes liquid of about 60°C.
41-6
4
Air conditioner
STRUCTURE AND FUNCTION
FUNDAMENTALS OF AIR CONDITIONING
[Reference]
• Refrigerant HFC134a (R134a)
HFC134a is used as the refrigerant of air conditioners for the following reasons.
1. HFC134a does not break the ozone layer which preserves the global environment.
2. HFC134a has much heat of vaporization and liquefies easily.
3. HFC134a does not burn or explode.
4. HFC134a is not toxic or corrosive and does not injure foods and clothes.
5. It is easy to obtain HFC134a.
• Substitutive Freon
CFC12 (R12) which was a conventional Freon (halogenated carbide containing fluorine) had been used
for air conditioners of construction machines. In 1996, however, it was resolved in Montreal World
Conference that CFC12 should not be used any more to preserve the global environment.
As a result, HFC134a (R134a) which does not break the ozone layer is used as a substitute for the
conventional Freon.
Air conditioner
41-7
4
STRUCTURE AND FUNCTION
FUNDAMENTALS OF AIR CONDITIONING
4. Refrigerating cycle of air conditioner
The refrigerating cycle of an air conditioner consists of a compressor, condenser, receiver tank,
expansion valve, evaporator, etc. The refrigerant is circulated in this cycle to absorb the indoor heat
with the evaporator and radiate it outside through the condenser.
Evaporator
Cool air
Expansion valve
Service
valve on
low-pressure
side
Indoor air
Refrigerant
liquid
Low-pressure and
low-temperature
refrigerant mist
Heat sensor tube
Indoor air
Sight glass
High-pressure and hightemperature gas
Service valve
on highpressure side
Hot air
Desiccant
Compressor
Receiver tank
Condenser
Cooling air from front side
The structure of the expansion valve is different and the receiver tank is added in the above cycle
compared to the basic refrigerating cycle described before.
To cool the air efficiently, much refrigerant must vaporize in the evaporator. In addition, all the
refrigerant must vaporize at the evaporator outlet.
41-8
4
Air conditioner
STRUCTURE AND FUNCTION
FUNDAMENTALS OF AIR CONDITIONING
The environment and structure of a construction
machine air conditioner are different from a home
air conditioner in the following points.
1 Indoor temperature varies largely.
The temperature in the operator’s cab is affected by
the outside temperature largely. It becomes very
high particularly when the machine is parked under
a burning sun in summer.
That is, The necessary quantity of the refrigerant in
the refrigerating cycle varies largely.
2 Compressor speed varies largely.
The compressor speed of the home air conditioner
is kept constant by the motor.
On the other hand, the compressor of the construction machine air conditioner is driven with the engine and its speed varies largely.
That is, The circulation rate of the refrigerant in the
refrigerating cycle varies largely.
To solve these problems, the expansion valve does
not only work as a simple choke valve but regulates
the circulation rate of the refrigerant automatically
according to the compressor speed and air conditioning load. For this purpose, the receiver is installed to store excessive refrigerant temporarily.
An actual construction machine air conditioner has
various devices to control temperature, air flow, etc.
and keep the operator’s cab comfortable.
Air conditioner
41-9
4
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
CONFIGURATION OF REFRIGERATING CYCLE
1. Structure of each refrigerating cycle part
An air conditioner consists of many functional parts. The refrigerating cycle parts among them are
mainly explained below.
fl The diagram shows a general example of system. The shape of each unit may differ according to
the machine model.
Evaporator
Expansion valve
Pressure switch
Compressor
Receiver tank
Condenser
41-10
4
Air conditioner
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
•
Layout of refrigerating cycle
fl The diagram shows the equipment for the D475A-3.
1.
2.
3.
4.
5.
6.
7.
8.
Air conditioner compressor
Condenser
Refrigerant piping
Window defroster
Side defroster
Air conditioner unit
Air outlet
Blower motor
Air conditioner
9.
10.
11.
12.
13.
Valve (Hot water outlet)
Hot water output piping
Receiver tank
Hot water return piping
Valve (Hot water inlet)
A. Outside air
B. Inside air
C. Hot air/Cool air
41-11
4
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
2. Compressor
The compressor compresses the refrigerant gas which absorbed the indoor heat through the evaporator so that it will be liquefied easily and sends it to the high-pressure side again.
The types of the compressor are classified by the structure as shown below.
1 Swash plate type
2 Through vane type
3 Sliding vane type
4 Scroll type
In addition to the above, the variable-capacity compressor is also used. Its capacity changes according
to the necessary air conditioning capacity. The swash plate-type compressor is explained below.
2.1 Swash plate-type compressor
Pressure relief valve
Shaft seal
Rear housing
Magnetic clutch
Piston
Cylinder
Swash plate
Front housing
41-12
4
Air conditioner
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
(1) Structure
In the swash plate-type compressor, 3 pairs (6 cylinders) or 5 pairs (10 cylinders) of pistons are set to
the swash plate fixed to the shaft diagonally. If the shaft rotates, the swash plate reciprocates the
pistons in the axial direction of the shaft.
Both ends of each pair of the pistons are in cylinders. When the cylinder of one end of the pistons is
in the compression process, the cylinder of the other end is in the suction process.
Cylinder
Piston
Swash plate
Piston
Shaft
Piston
Arrangement of pistons (10 cylinders)
Principle of swash plate type compressor
On the valve plate at the cylinder end, there are a
suction hole and a discharge hole to which a suction valve and a discharge valve are installed respectively.
The inside of the compressor is lubricated with the
compressor oil containing in the refrigerant gas and
the oil splashed by the centrifugal force of the swash
plate. Some models are lubricated forcibly with compressor oil by an oil pump.
Discharge valve
Cylinder
Discharge
Suction
Valve plate
Suction valve
Piston
Note: Both valves are kept
closed in stationary
state.
Air conditioner
41-13
4
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
(2) Operation
Discharge valve
Discharge valve
Suction valve
Suction valve
1 Suction
As the swash plate rotates, the pistons move. If a piston moves and the cylinder capacity is increased
and the pressure in the cylinder lowers below the pressure on the low-pressure side of the refrigerating cycle, the suction valve is pushed open and the refrigerant gas flows in the cylinder. At this time,
the discharge valve is fitted to the valve plate by the pressure on the high-pressure side to block the
discharge hole of the valve plate. Accordingly, the refrigerant gas does not flow back from the highpressure side into the cylinder.
2 Compression
If the cylinder capacity is reduced and the pressure in the cylinder rises above the pressure on the
discharge side (high-pressure side), the discharge valve opens and the high-temperature and highpressure refrigerant gas is sent to the condenser. At this time, the suction valve is fitted to the valve
plate by the pressure in the cylinder to block the suction hole of the valve plate. Accordingly, the
refrigerant gas does not flow back into the suction side (low-pressure side).
41-14
4
Air conditioner
STRUCTURE AND FUNCTION
[Reference]
• Pressure relief valve
If the pressure on the high pressure side of the
refrigerating cycle rises abnormally for some reason, the pressure relief valve of the compressor
discharges a part of the refrigerant.
Usually, however, the high-pressure pressure switch
installed to the control system operates first to stop
the compressor. Accordingly, the pressure relief
valve does not operate immediately.
CONFIGURATION OF REFRIGERATING CYCLE
Pressure relief valve
fl Once the pressure relief valve operates, remove
the cause. If the cause is not removed, the pressure relief valve will operate again.
Gas discharge path when
relief valve operates
Air conditioner
41-15
4
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
3. Magnetic clutch
Magnetic clutch
The air conditioner compressor is driven with the
engine. Accordingly, it must be stopped or started
again when the temperature reaches the set temperature or rises high. The magnetic clutch installed
to the compressor is used for this purpose.
The clutch hub of the magnetic clutch is fitted to the
crankshaft of the compressor. While the compressor is turned off, only the pulley rotates. If the air
conditioner switch is turned on, a current flows in
the coil embedded in the stator. As a result, the
stator becomes a strong electromagnet and attracts
the clutch hub and the compressor rotates together
with the pulley.
Center piece
Pulley
Damper
Compressor
shaft
Stator coil
Principle
Rotor
Stator coil
Snap ring
Bearing
Stator
Center piece
Structure
41-16
4
Air conditioner
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
4. Condenser
The condenser cools the high-temperature and high-pressure refrigerant gas sent from the compressor to liquefied it.
The condenser consists of tubes, fins, and a fan motor and is installed to the machine body.
The refrigerant gas discharged from the compressor is about 1.7 MPa {about 17 kg/cm2} in pressure and
about 80°C in temperature, for example. When this refrigerant passes through the tubes, it is cooled and liquefied.
Note: The pressure and temperature of the refrigerant vary with the atmospheric temperature, operating condition, etc.
5. Receiver tank
The refrigerant liquefied in the condenser is stored in
the receiver temporarily so that it can be supplied to
the evaporator according to the air conditioning load.
The receiver tank has strainers and desiccant in it to
remove "dirt" and "moisture" contained in the refrigerating cycle.
If there is moisture in the refrigerating cycle, it can corrode the functional parts and can be frozen in the
small hole of the expansion valve to block the refrigerant flow.
a In this case, replace the receiver tank since the
absorbing performance of the desiccant is lost.
If the strainer is clogged badly (If the high pressure rises and the low pressure lowers), replace
the receiver tank since the strainer cannot be
cleaned.
[Reference]
• Separation of refrigerant gas and liquid
The receiver tank does not only store the refriegerant temporarily but separates the refrigerant gas and
liquid.
All the refrigerant cooled in the condenser may not be
liquefied, depending on the atmosphere condition. If
the refrigerant gas is sent to the expansion valve, the
air conditioning capacity is lowered. The refrigerant
liquid is accumulated on the lower side of the receiver
tank and the refrigerant gas is accumulated on the
upper side. Since the refrigerant is taken out through
the outlet pipe installed to the bottom of the receiver
tank, the gas is separated from the liquid.
Air conditioner
Desiccant
Strainer
Refrigerant gas
Refrigerant liquid
41-17
(6)
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
6. Expansion valve
The expansion valve has the following 2 functions.
(1) Expand the high-temperature and high-pressure
refrigerant liquid sent from the receiver rapidly
and change it to low-temperature and low-pressure mist by spouting it through a small hole.
(2) Regulate the refrigerant flow rate according to
the vaporizing condition of the refrigerant in the
evaporator.
Expansion valve
Evaporator
To utilize the evaporator capacity fully, the refrigerant liquid must so absorb the heat from the air around the
evaporator that it will vaporize completely at the evaporator outlet.
For this porpose, the refrigerant flow rate is regulated automatically according to the fluctuation of the indoor
temperature (air conditioning load) and the fluctuation of the compressor speed.
a If the refrigerant flow rate is insufficient, the refrigerant in the evaporator vaporizes early and the cooling effect
lowers. If the former is too high, on the other hand, the excessive refrigerant liquid does not vaporize but returns to the compressor, and the cooling effect lowers and the compressor valve is damaged.
6.1 Regulation of refrigerant flow rate
The refrigerant flow rate is regulated basically with the diaphragm chamber and the needle valve coupled with it.
In the following figure, chamber A of the diaphragm chamber is filled with the refrigerant gas and sealed. The
pressure in chamber A is high (low) when the refrigerant temperature near the evaporator outlet is high (low).
(Since how the pressure in chamber A changes depends on the structure of the expansion valve, the concrete operation is explained later.)
On the other hand, the evaporation pressure in the evaporator is applied from near the evaporator outlet to
chamber B. While the refrigerant flow rate is constant, the diaphragm keeps the opening rate of the needle
valve constant with the pressure in chambers A and B and the force of the spring. If the air conditioning load
(indoor temperature, etc.) changes, the pressure in chamber A changes and moves the needle valve to the
right or left to regulate the refrigerant flow rate.
From receiver tank
Needle valve
(High pressure)
Diaphragm
Filled with refrigerant gas
and sealed
Spring
Refrigerant temperature near
evaporator outlet is transmitted.
Evaporator
To compressor
(Low pressure)
41-18
(6)
Air conditioner
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
6.2 Expansion valve (Box type)
(1) Structure
(Evaporator)
The box-type expansion valve consists a diaphragm,
heat sensor rod, needle valve (ball), etc. The upper
part of the diaphragm is filled with the refrigerant
and sealed.
The pressure at the evaporator outlet is applied to
the lower part of the diaphragm.
Diaphragm
Spring
Heat sensor
rod
Needle
(From receiver valve
tank)
(To compressor)
(2) Operation
The heat sensor rod senses the refrigerant temperature after it passes through the evaporator. The
temperature at this time is transmitted through the heat sensor rod to the refrigerant gas in the upper
part of the diaphragm chamber. As a result, the gas pressure changes according to the temperature
and moves the heat sensor rod coupled with the diaphragm to regulate the opening rate of the needle
valve.
• When evaporator outlet temperature is low (When air conditioning load is low)
The gas pressure in the diaphragm chamber lowers and the gas volume decreases. As a result, the
heat sensor rod moves to the right to close the needle valve.
• When evaporator outlet temperature is high (When air conditioning load is high)
The gas pressure in the diaphragm chamber rises and the gas volume increases. As a result, the
heat sensor rod moves to the left to open the needle valve, and more refrigerant is supplied to the
evaporator.
(Evaporator)
Heat sensor rod
Diaphragm
From receiver tank
(High pressure)
Air conditioner
Needle
valve
To compressor
(Low pressure)
41-19
4
STRUCTURE AND FUNCTION
[Reference]
• Expansion valve of even internal pressure type
If the evaporator capacity is relatively little, this expansion valve of even internal pressure type is used.
In this type, the evaporation pressure of the evaporator under the diaphragm is applied through the
small hole (inlet of the evaporator) in the expansion
valve. The other structure and operation are the
same with the conventional type described above.
CONFIGURATION OF REFRIGERATING CYCLE
Capillary tube
Diaphragm
Needle valve
Refrigerant inlet
Heat
sensor
tube
Pressure spring
Adjusting screw
Pe: Evaporator inlet pressure
Ps: Spring force
Pf: Pressure in heat sensor tube
• Expansion valve of even external pressure type
If the evaporation pressure is sensed at the inlet of
a large-sized evaporator, it is affected by the internal path resistance. To avoid this, an even-pressure
tube is passed from near the evaporator outlet to
sense the pressure. The above described conventional valve is this type.
[Evaporator inlet]
Liquid
100%
State of
refrigerant
• Flow regulation standard of expansion valve
To efficiently cool the indoor air which passes
through the evaporator, the refrigerant in the evaporator must vaporize well to cool the air and must
vaporize completely near the evaporator outlet.
The figure at right shows this state of the refrigerant. The refrigerant liquid and gas are mixed together, that is, the refrigerant vapor is saturated in
the part from the evaporator inlet to point A. Accordingly, the temperature is kept constant in this
part. All the refrigerant is evaporated completely in
the part from point A to point B, however, and its
temperature rises (Superheated vapor).
The flow regulation standard of the expansion valve
is so set that the superheating temperature of the
refrigerant vapor will be constant (e.g. 10°C).
[Evaporator outlet]
Temperature
is constant.
Gas
Liquid
Superheating
temperature
(10°C)
Gas
100%
Saturated vapor
(Mixture of liquid
Superheated vapor
and gas)
(Gas 100%)
Diaphragm
Capillary tube
Needle valve
External even-pressure tube
Refrigerant
inlet
Pressure
spring
Part of
saturated
vapor
41-20
4
Part of
superheated
vapor L
Air conditioner
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
7. Evaporator
The refrigerant mist cooled and decompressed
through the expansion valve vaporizes in large quantities. As a result, the evaporator is cooled.
The warm air in the cab is moved and cooled
through the evaporator by the fan. If the warm air is
cooled below the dew point by the evaporator fins,
the moisture in it condenses into water drops on
the evaporator fins. These water drops are discharged through the drain hose out of the cab.
Serpentine type
(1) Cooler unit
An actual evaporator has an expansion valve, thermistor, etc., and they are handled as a unit. It is
equipped with a blower motor and even a heater core on some models.
Evaporator
Expansion valve
Thermistor
Outside view
Inside of unit
(2) Thermistor
The thermistor is installed to the rear of the evaporator to sense the temperature of the air just after
cooled by the evaporator.
Air conditioner
41-21
4
STRUCTURE AND FUNCTION
CONFIGURATION OF REFRIGERATING CYCLE
8. Sight glass
The sight glass is "an window" to observe the condition of the refrigerant flowing through the refrigeranting cycle. Generally, if bubbles are seen in this
window, the refrigerant is insufficient. If the quantity
of the refrigerant is proper, no bubbles are seen.
The sight glass is usually installed to the top of the
receiver. If it cannot be used at that position, it may
be installed to the piping.
Sight glass
a No bubbles are seen, too, when there is not refrigerant (or there is too much refrigerant).
a When HFC134a is used, if the testing conditions
such as the compressor speed, pressure, etc.
are wrong, bubbles are seen.
a If the operation of the air conditioner is continued
while the refrigerant is insufficient, the compressor may be broken.
41-22
(6)
Air conditioner
STRUCTURE AND FUNCTION
CONTROL SYSTEM
CONTROL SYSTEM
To use the functions of the air conditioner fully and keep the inside of the cab comfortable, the air
outlet mode and various items, as well as the temperature and air flow, must be controlled.
1. Outline of control
1.1 Control panel
fl The figure below shows the control panel of D375A.
Air conditioner switch
Blower switch
Circulated air and fresh air selector switch
Temperature control switch
1 Temperature control switch
Used to control the temperature steplessly from low level to high level.
2 Circulated air and fresh air selector switch
Used to select “Fresh air” or “Circulated air”.
3 Blower switch
Used to set the air flow to 3 levels.
4 Air conditioner switch
Used to turn on and off the air conditioner.
Air conditioner
41-23
4
STRUCTURE AND FUNCTION
CONTROL SYSTEM
1.2 Contents of control
The main controls of the air conditioner are as follows.
Item
Outline of control
•
The temperature of the air cooled by the evaporator is measured with a thermistor and the compressor is turned on and
off automatically at the set temperatures.
•
The blower motor speed is set to 3 levels.
•
•
The damper to select fresh air or circulated air is controlled.
The damper to select air outlet in the cooling mode and
heating mode is controlled.
4. Defrosting control
•
•
Frosting of the evaporator is prevented.
Thermistor is used for this control.
5. Compressor control
•
Abnormal refrigerant pressure is detected.
1. Temperature control
2. Air flow control
3. Circulated air and fresh
air selection
2. Temperature control
2.1 Thermistor method
When the cooler unit and heater unit are independent from each other and the airs from them cannot
be mixed, the thermistor method is applied. The
thermistor is a semiconductor, the resistance of
which varies remarkably with the temperature. As
shown in the figure, the resistance of the thermistor
decreases as the temperature rises, and increases
as the temperature lowers.
The thermistor is installed to the rear of the evaporator to sense the temperature of the air flowing
through the evaporator.
The temperature control switch is on the control
panel. The temperature is controlled by comparing
the signal of the temperature control switch (desired temperature) with the signal of the thermistor
in the air conditioner amplifier and turning on and
off the compressor through the magnetic clutch.
The signal of the thermistor is used to prevent frosting of the evaporator, too (This is described later).
Thermistor
Structure
Resistance
Temperature (°C)
Characteristics of thermistor
41-24
4
Air conditioner
STRUCTURE AND FUNCTION
CONTROL SYSTEM
3. Air flow control
Fresh air
The quantity of the air blown into the cab is controlled by adjusting the blower motor speed.
The blower motor is a ferrite motor. Its speed (air flow)
is controlled to 3 levels by changing the resistor
conected to the motor in series with the blower switch
as shown in the circuit diagram.
Circulated
air
[Reference]
• Motor speed
The speed (N) of a DC motor is in proportion to the
motor terminal voltage (V) and in inverse proportion
to the magnetic flux (ø).
Ferrite magnet
Speed N = K V/ø
q
If ferrite magnets are used, the magnetic flux (ø) is
constant. Accordingly, the speed is controlled by
changing the voltage applied to the motor with the
resistor connected to the motor in series.
4. Circulated air and fresh air selection
If the circulated air and fresh air selector switch on the control panel is operated, the damper moves to select
the fresh air or the circulated air.
Fresh air:
The outside air is taken into the cab. This mode is selected normally.
Circulated air: This mode is used when the outside air is dirty or you need to cool or heat the cab quickly.
Air conditioner
41-25
(6)
STRUCTURE AND FUNCTION
CONTROL SYSTEM
5. Defrosting control
If warm air blows against the evaporator fins and cooled there, the moisture in the air condenses into water
drops on the evaporator fins. If the fin temperature is below 0°C at this time, the water drops are frozen or
frosted. This phenomenon is called frosting. If frosting occurs, the heat exchange efficiency of the evaporator
lowers and the full cooling capacity is not obtained.
Frosting can be prevented by the following method.
Thermostat method (ON/OFF switch)
The evaporator temperature is sensed from the signal of the evaporator sensor installed to the rear of
the evaporator. The compressor is turned OFF before the evaporator is frosted.
Evaporator
sensor
41-26
(6)
Air conditioner
STRUCTURE AND FUNCTION
CONTROL SYSTEM
6. Compressor control
Location of pressure switch
Judgment of abnormal refrigerant pressure
Receiver
tank
Condenser
Expansion valve
Evaporator
The pressure on the high-pressure side of the refrigerating cycle is sensed with a pressure switch. If
it rises high abnormally, the compressor is stopped
to prevent a trouble in the refrigerating cycle devices.
Generally, the refrigerant pressure is sensed with a
pressure switch installed between the receiver tank
on the high-pressure side and expansion valve.
Compressor
(1) Pressure switch
The pressure switch is a dual type, that is, it can
detects both abnormally high pressure and abnormally low pressure.
Contact
mechanism
1 Detection of abnormally high pressure
If the high pressure in the refrigerating cycle rises
abnormally, it can cause a trouble or breakage of
the devices.
Generally, the pressure switch to detect high pressure is turned off when the pressure rises above
about 3.1 MPa {32 kg/cm2}.
Structure
Characteristics
2 Detection of abnormally low pressure
When the refrigerant in the refrigerating cycle is
extremely insufficient or lost completely because of
leakage, etc., if the compressor is started, it is not
lubricated well and may be seized. To prevent this,
the pressure switch turns off the compressor when
the pressure on the high-pressure side lowers below about 0.2 MPa {2.0 kg/cm2} because of insufficiency of the refrigerant.
Air conditioner
41-27
4
TROUBLESHOOTING
TESTING AND ADJUSTING
DENSO (NEW REFRIGERANT TYPE)
Service tools
1. Service tool kit ....................................................................................................................................... 42- 2
2. Gauge manifold ..................................................................................................................................... 42- 3
3. Gas leak detector .................................................................................................................................. 42- 7
4. Vacuum pump........................................................................................................................................ 42- 8
5. Service can valve .................................................................................................................................. 42- 9
6. Belt tension gauge................................................................................................................................. 42- 10
7. Connection of service tools ....................................................................................................................42- 11
Troubleshooting
1. Troubleshooting procedure.................................................................................................................... 42- 12
2. Inspection of refrigerating cycle............................................................................................................. 42- 19
3. Check for abnormal noise...................................................................................................................... 42- 27
4. Electric system ...................................................................................................................................... 42- 29
5. Replacement of parts ............................................................................................................................ 42- 30
Charging with refrigerant
1. Precautions for charging with refrigerant............................................................................................... 42- 32
2. Evacuation............................................................................................................................................. 42- 34
3. Charging with refrigerant ....................................................................................................................... 42- 37
4. Check of quantity of refrigerant ............................................................................................................. 42- 41
Periodic inspection and maintenance
1. Inspection and maintenance items ........................................................................................................ 42- 44
2. Check of quantity of refrigerant ............................................................................................................. 42- 45
3. Inspection of functional parts................................................................................................................. 42- 46
Air conditioner
42-1
(5)
TESTING AND ADJUSTING
SERVICE TOOLS
SERVICE TOOLS
The following tools and devices are necessary for servicing the air conditioners.
(1) Service tool kit
(2) Vacuum pump
(3) Torque wrench
(4) Belt tension gauge
(5) Gas leak detector
(6) General tools
1. Service tool kit
The service tool kit is a kit of the gauge manifold and the small tools shown below.
Gauge manifold
Low-pressure charging
hose (Blue)
High-pressure charging
hose (Red)
Quick joint
(LO)
Center charging hose
(Green)
Service can T-joint
Quick joint
(HI)
Service can valve
Service tools for HFC134a
fl For air conditioners which use HFC134a (R134a), use the service tool kit for HFC134a, the joints of
which are so changed that the air conditioners will not be charged with wrong refrigerant.
42-2
4
Air conditioner
TESTING AND ADJUSTING
SERVICE TOOLS
2. Gauge manifold
The gauge manifold is used to check the operating pressure of the refrigerating cycle, evacuate the
refrigerating cycle, and charge the refrigerating cycle with refrigerant.
2.1 Structure of gauge manifold
The knobs on the front side of the gauge manifold are used to open and close the valves securely. The
marks of “LO” and “HI” on those knobs denote the “low-pressure valve” and “high-pressure valve”
respectively.
Low-pressure gauge
High-pressure gauge
Low-pressure gauge
High-pressure gauge
Air purge
valve is built in.
Air purge valve
is built in.
Low-pressure valve
(LO)
High-pressure valve
(HI)
Outside view
Air conditioner
Low-pressure valve
(LO)
High-pressure valve
(HI)
Internal circuit
42-3
4
TESTING AND ADJUSTING
2.2 Handling of gauge manifold
SERVICE TOOLS
Closed
Closed
(2) When low-pressure valve (LO) is opened and
high-pressure valve (HI) is closed
Open
Closed
(3) When low-pressure valve (LO) is closed and
high-pressure valve (HI) is opened
Closed
Open
(4) When both low-pressure valve (LO) and highpressure valve (HI) are opened
Open
Open
You can form the following 4 circuits by opening or
closing the high-pressure and low-pressure valves.
(1) When both low-pressure valve (LO) and highpressure valve (HI) are closed
42-4
4
Air conditioner
TESTING AND ADJUSTING
SERVICE TOOLS
2.3 Charging hoses
The 3 charging hoses are colored in blue, green,
and red. Connect the blue hose to the low-pressure
side, the green one to the central adapter, and the
red one to the high-pressure side.
When storing the gauge manifold, be sure to connect each charging hose to an adapter to prevent
“dirt” and “water” from entering the gauge manifold.
Blue
Red
The nut at the end of each hose has packing in it. If
you screw it lightly over the mating adapter, it is
connected securely. You do not need to tighten it
with priers, etc.
Green
Air conditioner
42-5
4
TESTING AND ADJUSTING
2.4 Quick joint
SERVICE TOOLS
Quick joint
Charging hose
With the quick joint (having a check valve), you can
connect each hose of the gauge manifold to the
charging valve in an instant.
Charging valve
(1) Connection of quick joint
Press the quick joint against the charging valve and
push part A until a click is heard.
Sleeve
“Click”
fl When pressing the quick joint to connect it, take
care not to bend the pipe.
fl If the sleeve has moved without connecting the
joint to the charging valve, set it to the original
position again, then try again.
fl If any refrigerant is left in the charging hose, the
quick joint may not be connected easily. In this
case, release the residual pressure from the hose.
Press the pusher to release
the residual pressure.
(2) Disconnection of quick joint
Securing part A of the quick joint, slide up part B
(sleeve).
Sleeve
“Click”
fl After disconnecting the quick joint, cap the charging valve.
42-6
4
Air conditioner
TESTING AND ADJUSTING
SERVICE TOOLS
3. Gas leak detector
The gas leak detector is an electric tester used to check each joint of the refrigerating cycle for
refrigerant leakage.
Apply the probe to a part to be checked and move it slowly to check for leakage. If any refrigerant
leaks from that part, the sounding intervals and flashing intervals become short.
This leak detector can be used for both HFC134a (R134a) and R12 which is used for the conventional
air conditioners.
Battery charger
Internal battery
Sensor (Under cover)
Speaker
Sensitivity selector switch
Suction probe
Power switch
Check leak bottle
Gas leak detector
fl The conventional leak tester of halide torch type cannot detect HFC134a (R134a) which does not
contain chlorine.
Air conditioner
42-7
4
TESTING AND ADJUSTING
SERVICE TOOLS
4. Vacuum pump
When charging a refrigerating cycle with refrigerant, you must remove the all water from it. For this
purpose, the refrigerating cycle is evacuated with a
vacuum pump (Evacuation will be described later).
fl When a vacuum pump for conventional refrigerant R12 is used for HFC134a (R134a), a vacuum
pump adapter is necessary. With this adapter,
the above vacuum pump can be used for both
HFC134a (R134a) and R12.
[The current vacuum pump (manufactured by
our company) can be used for both new and
conventional refrigerants.]
[Reference]
• Vacuum pump adapter
After the refrigerating cycle of an air conditioner is
evacuated, if the vacuum pump is stopped, the oil
in the vacuum pump flows back into the charging
hose since the inside of the gauge manifold hose is
a vacuum. If the refrigerating cycle is charged with
the refrigerant under this condition, the vacuum
pump oil left in the charging hose flows together
with the refrigerant into the refrigerating cycle.
The adapter equipped with a solenoid valve is used
to prevent the backflow of the oil from the vacuum
pump.
If the solenoid valve is turned on, it closes to stop
the inflow of the atmosphere and the refrigerating
cycle can be evacuated. If it is turned off, it allows
inflow of the atmosphere and the refrigerating cycle
cannot be evacuated.
Vacuum pump adapter
Solenoid valve
Atmosphere
Atmosphere
Blind cap
42-8
4
Vacuum
pump
Air conditioner
TESTING AND ADJUSTING
SERVICE TOOLS
5. Service can valve
Handle
The service can valve is used to supply the refrigerant from a service can to the refrigerating cycle.
Handling method
1 Turn the handle to the left end to raise the
needle. Be sure to raise the disc at this time,
too.
2 Screw the service can valve into the service can,
then tighten the disc. At this time, take care
sufficiently not to damage the service can by
tightening the disc too strongly.
3 Install the charging hose (green) of the gauge
manifold to the valve.
4 Turn the handle of the service can valve to the
right to lower the needle and make a hole in the
service can.
5 Turn the handle to the left to raise the needle,
and the refrigerant flows through the valve into
the refrigerating cycle.
6 To stop supplying the refrigerant, turn the handle
to the right end to lower the needle.
Hose adapter
Needle
Disc
Packing
Service can
fl Check that the packing is usable. If the packing
is coated with compressor oil, it lasts long.
Air conditioner
42-9
4
TESTING AND ADJUSTING
SERVICE TOOLS
6. Belt tension gauge
If the belt tension is not proper, the lives of the
bearings and belt are shortened. The belt tension gauge is used to measure the belt tension
correctly and easily. Be sure to use this gauge
particularly to adjust the tension of the V-belt.
If the remote cable is connected to the belt tension gauge, you can measure the belt tension efficiently
even if the engine compartment is narrow.
Remote cable
42-10
4
Air conditioner
TESTING AND ADJUSTING
SERVICE TOOLS
7. Connection of service tools
Connect the gauge manifold, vacuum pump, and other service tools as shown below.
(1) Close the high-pressure valve (HI) and low-pressure valve (LO) of the gauge manifold.
(2) Connect the red (HI) and blue (LO) charging hoses to the service valves of the high-pressure and
low-pressure pipes. The service valves may be installed to the compressor. Use the quick joints to
connect the hoses.
(3) Connect the green hose at the center of the gauge manifold to the following parts.
1 For evacuation: Connect to the vacuum pump.
fl Be sure to use the vacuum pump adapter.
2 For charging with refrigerant: Connect to the service can valve of the service can.
High-pressure valve
Vacuum pump
Low-pressure valve
Blue
quick joint
Red
Green
Service can valve
Service valve on low-pressure side
Service valve
on highpressure side
Refrigerant can
Compressor
 When connecting the charging hoses, take care not to mistake the high-pressure side and lowpressure side of the gauge manifold.
fl Connect the quick joints at the ends of both high-pressure hose and low-pressure hose. If either
one is not connected, the atmosphere enters it and a vacuum is not obtained. (The check valve of
the quick joint cannot maintain a vacuum.)
Air conditioner
42-11
4
TESTING AND ADJUSTING
TROUBLESHOOTING
TROUBLESHOOTING
1. Troubleshooting procedure
The following figure shows the basic troubleshooting procedure.
The troubles of an air conditioner are roughly classified into the troubles of the refrigerating cycle and
those of the electric system. In this chapter, the troubleshooting method is explained according to the
basic procedure.
Examination by interview
Confirmation of trouble
Basic inspection
• Control mechanism
• V-belt
• Sight glass
• Pipe joints
Troubleshooting
Inspection of
refrigerating cycle
Check for abnormal noise
Inspection of
electric system
Replacement of parts
(Repair and check)
Completion
42-12
4
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
1.1 Examination by interview and confirmation of trouble
Before carrying out troubleshooting, you must check
the contents and condition of the trouble thoroughly.
If the trouble occurs sometime or cannot be reproduced, “examination by interview” to obtain the
occurrence condition of the trouble is important.
<Points of examination by interview>
• What
Model and serial No.
• When
Date, time, and frequency of occurrence
• Where
Condition of working place
• Condition
Working condition, and weather
• How
How operator felt about trouble
1.2 Basic inspection
(1) Inspection of Control mechanism
Operate the levers and switches on the control panel
to see if they work smoothly and securely.
s Check the fuses, if necessary.
(2) Inspection of V-belt
Check that the belt tension is proper and belt is not
damaged.
(3) Inspection of quantity of refrigerant through
sight glass
If many bubbles are seen in through the sight glass,
the refrigerant may be insufficient. In this case, inspect with the gauge manifold.
(For the criterion, see 4.2 CHARGlNG WITH REFRIGERANT, inspection through sight glass.)
(4) Inspection of pipe joints
If a pipe joint is coated with oil, the refrigerant may
be leaking through it. In this case, wipe off the oil
and check for refrigerant leakage.
Air conditioner
42-13
4
(5)
TESTING AND ADJUSTING
TROUBLESHOOTING
1.3 Troubleshooting
1.3.1 Troubles in cooling mode
DEFROSTER-FACE mixed blow type
Cause
a. Air flow is insufficient
YES
2
YES Is rotation
normal?
1
Does blower
motor rotate?
NO
Remedy
• Clogging of indoor air filter
• Clogging of outdoor air filter
• Obstacle near air suction opening
• Deformed or broken blower
• Frosting of evaporator
• Clean filter
• Clean filter
• Remove obstacle
• Replace blower
• Stop air
conditioner and
melt ice
Go to Causes and
remedies of
troubles, A
• Dirt sticking to evaporator surface • Clean evaporator
surface
• Low source voltage
• Check battery
charge system
• Bad contact of battery terminal
• Repair
• Defective blower motor
• Replace
• Defective blower Hl relay
• Replace
• Breakage of resistor
(Blower rotates at only Hl)
• Breakage of fuse
• Replace
NO
• Defective power-up relay on
machine side
• Defective blower motor
• Interference of blower with case
• Defective blower switch
• Defective grounding to chassis
• Defective wiring or
disconnection of connector
b. Air flow is normal
• Entry of outside air
• Removal of air mixing link
YES Is compressor
pressure normal?
1
Does compressor rotate normally?
NO
NO
• Pressure on low-pressure side
is too high
(Above about 0.29 MPa)
• Pressure on high-pressure side
is too low
(Below about 0.98 MPa)
• Pressure on low-pressure side
is too low
(Below about 0.05 MPa)
• Pressures on both highpressure side and low-pressure
side are high
• Pressures on both highpressure side and low-pressure
side are low
• Go to Causes and
remedies of
troubles, C-2
• Go to Causes and
remedies of
troubles, C-3
• Go to Causes and
remedies of
troubles, C-4
• Go to Causes and
remedies of
troubles, C-5
• Insufficient
refrigerant
• Breakage or slip of V-belt
• Defective compressor (Locked)
• Defective magnetic clutch
• Replace V-belt
• Replace
• Repair or replace
Go to Causes and
remedies of
troubles, D-1
• Check wiring
Go to Causes and
remedies of
troubles, D-2
• Clutch is not engaged because
of trouble in electric system
c. Refrigerant pressure is abnormally high or low
High-pressure cutting
system operates
Low-pressure cutting
system operates
42-14
(5)
• Replace
• Repair
• Replace panel
• Ground securely
• Check wiring
• Close windows
and door
Adjust Circulated
air and fresh air
selector damper
• Set link again
YES
2
• Replace fuse
Go to Causes and
remedies of
troubles, B
• Replace
• Go to Causes and remedies of
troubles, C-1
• Go to Causes and remedies of
troubles, C-3
-
-
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
DEFROSTER-FACE separate blow type
Cause
a. Air flow is insufficient
YES
2
YES Is rotation
normal?
1
Does blower
motor rotate?
NO
• Clean filter
• Clean filter
• Remove obstacle
• Replace blower
• Stop air
conditioner and
melt ice
Go to Causes and
remedies of
troubles, A
• Dirt sticking to evaporator surface • Clean evaporator
surface
• Low source voltage
• Check battery
charge system
• Bad contact of battery terminal
• Repair
• Defective blower motor
• Replace
• Defective blower Hl relay
• Replace
• Defective power transistor
• Replace
• Breakage of fuse
• Replace fuse
Go to Causes and
remedies of
troubles, B
• Replace
NO
• Defective power-up relay on
machine side
• Defective blower motor
• Interference of blower with case
• Defective blower switch
• Defective grounding to chassis
• Defective wiring or
disconnection of connector
b. Air flow is normal
• Entry of outside air
YES
2
• Removal of air mixing link
YES Is compressor
pressure normal?
1
Does compressor rotate normally?
NO
NO
Air conditioner
• Close windows
and door
Adjust Circulated
air and fresh air
selector damper
• Set link again
• Go to Causes and
remedies of
troubles, C-2
• Go to Causes and
remedies of
troubles, C-3
• Go to Causes and
remedies of
troubles, C-4
• Go to Causes and
remedies of
troubles, C-5
• Insufficient
refrigerant
• Breakage or slip of V-belt
• Defective compressor (Locked)
• Defective magnetic clutch
• Replace V-belt
• Replace
• Repair or replace
Go to Causes and
remedies of
troubles, D-1
• Check wiring
Go to Causes and
remedies of
troubles, D-2
c. Refrigerant pressure is abnormally high or low
Low-pressure cutting
system operates
• Replace
• Repair
• Replace panel
• Ground securely
• Check wiring
• Pressure on low-pressure side
is too high
(Above about 0.29 MPa)
• Pressure on high-pressure side
is too low
(Below about 0.98 MPa)
• Pressure on low-pressure side
is too low
(Below about 0.05 MPa)
• Pressures on both highpressure side and low-pressure
side are high
• Pressures on both highpressure side and low-pressure
side are low
• Clutch is not engaged because
of trouble in electric system
High-pressure cutting
system operates
Remedy
• Clogging of indoor air filter
• Clogging of outdoor air filter
• Obstacle near air suction opening
• Deformed or broken blower
• Frosting of evaporator
• Go to Causes and remedies of
troubles, C-1
-
• Go to Causes and remedies of
troubles, C-3
-
42-14-1
42-15
(5)
(5)
TESTING AND ADJUSTING
42-16
(5)
TROUBLESHOOTING
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
• Causes and remedies of troubles
No.
Cause
<DEFROSTER-FACE mixed blow type>
• Defective magnetic clutch circuit
• Defective frost sensor wiring
• Defective frost sensor characteristics
• Defective adjustment of gap between frost
sensor and evaporator (Defective sensitivity)
Remedy
• Check clutch circuit and replace relay
• Check for short circuit, then repair or replace
• Check characteristics and replace sensor
• Adjust gap to 12 v 5mm
Voltage is applied
to magnetic clutch
A
<DEFROSTER-FACE separate blow type>
• Defective magnetic clutch circuit
• Check clutch circuit and replace relay
• Check for short circuit, then repair or
• Defective thermostat wiring
replace
• Check operation and replace thermo• Malfunction of thermostat
stat
Voltage is not
applied to magnetic clutch
B
-
1
C
2
Air conditioner
• Defective magnetic clutch
• Replace
• Blower motor is locked
• Wrong wiring
• Short circuit of wiring
• Replace blower motor
• Repair
• Repair or replace
• Ambient temperature is abnormally high
• Insufficient cooling by condenser
- Fins are clogged with dirt and soil
• Too much refrigerant
• Air in refrigerating cycle
• Too much refrigerant
•Breakage of head gasket
• Defective
•Breakage of suction valve
compressor
•Foreign matter caught
in suction valve
• Expansion valve
•Defective valve
is opened too
•Bad contact of heat sensor
much
tube
-
• Clean fins(with water)
• Discharge refrigerant properly
• Discharge all refrigerant, then evacuate
refrigerating cycle and charge it with
refrigerant again by proper quantity
• Discharge refrigerant properly
• Replace compressor
• Replace
• Repair
42-15
42-17
(5)
TESTING AND ADJUSTING
No.
TROUBLESHOOTING
Cause
• Ambient temperature is abnormally low
• Refrigerant is insufficient
3
•Swash plate shoe is locked
•Piston is locked
•Defective suction/
discharge valve
• Defective
•Clogging of valve
expansion valve •Leakage of refrigerant
from heat sensor tube
•Tentative clogging by
freezing of valve
• Defective
compressor
• Ambient temperature is abnormally low
• Refrigerant is insufficient
C
4
• Clogging of refrigerating cycle
• Defective
expansion valve
•Clogging of valve
Leakage of refrigerant
from heat sensor tube
•Tentative clogging by
freezing of valve
• Frosting of evaporator
5
42-18
42-16
(5)
• Insufficient cooling by condenser
• Too much refrigerant
Remedy
• Charge with proper quantity of refrigerant
• Perform leak test and repair leaking part, then charge with refrigerant
• Replace compressor
• Replace valve
• Replace valve
• Replace valve and receiver, then
evacuate sufficiently
• Charge with proper quantity of
refrigerant
• Perform leak test and repair leaking part, then charge with refrigerant
• Replace receiver and dryer
• Replace piping
• Replace valve
• Replace valve
• Replace valve and receiver, then evacuate sufficiently
• (Go to A)
• Clean fins
• Discharge refrigerant properly
Air conditioner
TESTING AND ADJUSTING
No.
1
D
2
Air conditioner
TROUBLESHOOTING
Cause
Remedy
• Breakage of stator coil
• Too much air gap between rotor and stator
Key is broken or not
inserted
• Slip of clutch
Oil on clutch surface
Layer short circuit or
low battery voltage
• Foreign matter caught between rotor and
stator
• Replace
• Repair or replace
•
•
•
•
Remove oil
Replace
Charge
Overhaul
•
•
•
•
•
•
•
•
•
•
Replace control panel
Replace control panel
Replace
Replace
Replace
Defective air conditioner switch
Defective blower switch
Defective compressor clutch relay
Defective thermo-sensor
Defective refrigerant high-pressure/lowpressure switch
• Abnormally high Too high
pressure on
(above 2.5 MPa
high-pressure
{25 kg/cm2})
side
Too low
(below 0.9 MPa
{10 kg/cm2})
• Replace key
• (Go to C-1)
• (Go to C-4)
42-17
4
TESTING AND ADJUSTING
1.3.2
TROUBLESHOOTING
Troubles in heating mode
fl Be sure to check that the pump pressure is normal and the heater hoses IN and OUT are connected
correctly.
a. Air flow is insufficient
fl See 1.3.1 Troubles in cooling mode.
b. Air flow is normal
1 YES
Is hot water
temperature
normal?
1 YES
Does temperature
regulator LED
operate normally?
NO
1.3.4
• Air in hot water circuit
• Clogging or bend of piping
• Ambient temperature is very
low
• Engine water level is low
• Bleed air
• Repair or replace
—
• Supply water to
proper level
• Replace heater
core
• Entry of outside air
• Close windows
and door
• Disconnection of
temperature regulator
link
• Entry of foreign matter
• Set link again
• Defective or broken
wiring or disconnection
of connector
• Defective servomotor
• Check wiring
• Clogging of drain hole
• Clean
• Disconnection of link
• Set link again
• Defective or broken
wiring or disconnection
of connector
• Defective servomotor
• Entry of foreign matter
• Check wiring
• Remove
foreign matter
• Replace
Water leakage into cab
Defective selection of circulated air and fresh air
1 YES
Is circulated
air/fresh air
servomotor
normal?
NO
42-18
4
Remedy
• Breakage of heater core
NO
1.3.3
Cause
• Replace
• Remove
foreign matter
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
2. Inspection of refrigerating cycle
2.1 Inspection with gauge manifold
Measure the low pressure and high pressure of the refrigerating cycle with the gauge manifold under
the following condition, then carry out troubleshooting.
fl For connection of the gauge manifold, see 7. Connection of service tools.
<Condition>
Warm up the engine, then measure under the following condition.
• Door:
Open fully
• Air conditioner suction opening temperature: 30°C – 35°C
• Circulated air/Fresh air selector switch:
Circulated air
• Blower speed:
HI
• Engine speed:
1,500 rpm
• Temperature control:
Lowest temperature
fl The values indicated by the gauge manifold may vary more or less with the condition.
(1) When normal
The pressures must be as follows under the above
condition.
Pressure on low-pressure side:
0.15 – 0.25 MPa {1.5 – 2.5 kg/cm2}
Pressure on high-pressure side:
1.37 – 1.57 MPa {14 – 16 kg/cm2}
The illustrated gauges have only the divisions of SI
units. The actual gauges have the divisions of the
conventional units, too, however.
Low-pressure side
High-pressure side
Low-pressure side
High-pressure side
(2) When refrigerant is insufficient
•
Trouble
1 Both pressures on the low-pressure side and
high-pressure side are low.
2 Bubbles pass the sight glass continuously.
3 Air is not cooled well.
• Cause
1 Refrigerant is insufficient or it is leaking.
• Points of remedy
1 Check and repair refrigerant leaking point.
2 Charge with refrigerant again.
Air conditioner
42-19
4
TESTING AND ADJUSTING
(3) Too much refrigerant in refrigerating cycle
or insufficient cooling by condenser
• Trouble
1 Both pressures on the low-pressure side and
high-pressure side are high.
2 No bubbles are seen in the sight glass even in
the low speed range.
3 Air is not cooled well.
• Cause
1 Too much refrigerant is in the refrigerating cycle.
2 Insufficient cooling by the condenser.
• Points of remedy
1 Adjust the quantity of refrigerant properly.
2 Clean the condenser.
3 Inspect the cooling system of the machine (electric fan, etc.)
TROUBLESHOOTING
Low-pressure side
High-pressure side
Low-pressure side
High-pressure side
Low-pressure side
High-pressure side
(4) Water in refrigerating cycle
• Trouble
1 After a certain using time, the pressure on the
low-pressure side becomes negative gradually.
• Cause
1 Water is in the refrigerating cycle.
• Points of remedy
1 Replace the receiver tank.
2 Before charging the refrigerating cycle with refrigerant, evacuate it thoroughly to remove all
water.
(5) Insufficient compression by compressor
• Trouble
1 The pressure on the low-pressure side is high
and that on the high-pressure side is low.
2 Just after the air conditioner is turned off, the
pressures on the high-pressure side and lowpressure side become the same.
• Cause
1 The compressor is defective.
• Points of remedy
1 Inspect and repair the compressor.
42-20
4
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
(6) Refrigerant does not circulate (Refrigerating cycle is clogged)
• Trouble
1 If the refrigerating cycle is clogged completely,
the pressure on the low-pressure side becomes
negative soon. If the former is clogged a little,
the latter becomes negative gradually.
2 The temperatures before and after the clogged
part are different.
• Cause
1 Dirt, water, etc. block the small hole of the expansion valve or they are frozen, and the refrigerant does not flow.
• Points of remedy
1 Replace the receiver tank.
2 Evacuate the refrigerating cycle thoroughly.
Low-pressure side
High-pressure side
Low-pressure side
High-pressure side
Low-pressure side
High-pressure side
(7) Air in refrigerating cycle
• Trouble
1 Both pressures on the low-pressure side and
high-pressure side are high.
2 The low-pressure piping is not cold.
3 Bubbles are seen in the sight glass.
• Cause
1 Air in the refrigerating cycle.
• Points of remedy
1 Replace refrigerant.
2 Evacuate the refrigerating cycle thoroughly.
(8) Too wide opening of expansion valve
• Trouble
1 Both pressures on the low-pressure side and
high-pressure side are high.
2 Low-pressure piping is coated with frost (dews).
• Cause
1 The expansion valve does not work normally.
• Points of remedy
1 Check the installation condition of the heat sensor tube.
Air conditioner
42-21
4
TESTING AND ADJUSTING
TROUBLESHOOTING
2.2 Troubleshooting table
No.
Trouble
Related section
Condition
Possible cause
1
Pressure on
low-pressure
side is
abnormally
high
(above about
0.3 MPa {3.1
kg/cm2})
Compressor
Just after compressor is
stopped, pressures on highpressure side and low-pressure side become the same.
Defective compression by
compressor
Replace compressor
Expansion
valve
Both pressures on high-pressure side and low-pressure
side are high. Low-pressure
hose and parts near service
valve on low-pressure side are
abnormally cold and piping is
coated with frost (dews).
Expansion valve is opened
too wide (Defective adjustment)
Replace expansion valve
Bad contact (Removal) of
heat sensor tube
Stick heat sensor tube firmly
Both pressures on high-pressure side and low-pressure
side are high. If condenser is
cooled forcibly, pressure on
low-pressure side lowers.
Too much refrigerant in refrigerating cycle
Adjust quantity of refrigerant properly
Insufficient cooling by condenser
Clean condenser fins (with
water) or check and repair it
Check and repair cooling
system on machine side
(electric fan, radiator, etc.)
Condenser cooling fan does
not suck in air sufficiently
(Cooling air is insufficient)
Looseness or breakage of
fan belt
Tense or replace belt.
If electric fan is used, motor
is defective or fan slips
Replace motor or fix fan
Installation of fan in reverse
Install in normal direction
Fan shroud is not installed
Install genuine shroud
Condenser fins are clogged
with dirt
Clean condenser fins (with
water) or check and repair it
Insufficient cooling water or
oil
Charge with refrigerant to
proper level.
Wrong ignition timing
Adjust
Trouble or insufficient capacity of water pump
Repair or replace
Radiator fins are clogged
with dirt
Clean fins (with water)
Bubbles do not disappear
from sight glass even if condenser is cooled with water
Too much refrigerant in refrigerating cycle
Adjust quantity of refrigerant properly
Just after compressor stops,
pressure lowers by about 0.2
MPa {2 kg/cm2}
Air in refrigerating cycle
Replace refrigerant (Evacuate refrigerating cycle thoroughly)
Other
sections
Thermal load is too high
Ambient temperature is abnormally high
Cool condenser efficiently
Expansion
valve
Expansion valve is not frosted
and low-pressure piping is not
cold
Clogging of expansion valve
(Defective adjustment, entry
of foreign matter, etc.)
Replace expansion valve
Leakage of refrigerant from
heat sensor tube
Replace expansion valve
Temporary clogging of expansion valve caused by
freezing (Trouble by water in
refrigerating cycle)
Replace expansion valve, receiver tank, and drier, then
evacuate refrigerating cycle
thoroughly
Expansion valve is clogged
a little (Defective adjustment
or entry of foreign matter)
Replace expansion valve
Refrigerating
cycle
Pressure on
highpressure
side is
abnormally
high
(above about
2 MPa {20
kg/cm2})
2
Condenser
Engine
Refrigerating
cycle
3
Pressure on
low-pressure
side is
abnormally
low
(below about
0.05 MPa
{0.5 kg/cm2})
Engine is overheated
Expansion valve is frosted
42-22
4
Remedy
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
No.
Trouble
Related section
Condition
3
Pressure on
low-pressure
side is
abnormally
low
(below about
0.05 MPa{0.5
kg/cm2})
Refrigerating
cycle
Air is not cooled well and
bubbles pass through sight
glass continuously
5
6
7
Pressure on
highpressure
side is
abnormally
low
(below about
1 MPa{10 kg/
cm2})
Leakage of
refrigerant
and oil
Magnetic
clutch is not
engaged
Magnetic
clutch slips
Air conditioner
Remedy
Insufficient refrigerant
Charge with refrigerant to
proper level.
Leakage of refrigerant
Check and repair leaking part
Receiver tank and drier are abnormally cold (frosted)
Clogging of receiver tank
and drier
(Entry of foreign matter, etc.)
Replace receiver tank and
drier (Evacuate refrigerating
cycle thoroughly)
Blown air temperature is low
and air flow is little
Evaporator is frosted
Check and adjust amplifier
and thermistor
Thermal load is too low
Ambient temperature is abnormally low
—
Compressor
Just after compressor is
stopped, pressures on highpressure side and low-pressure side become the same.
Defective compression by
compressor
Replace compressor
Expansion
valve
Expansion valve is not frosted
and low-pressure piping is not
cold
Clogging of expansion valve
(Defective adjustment, entry
of foreign matter, etc.)
Replace expansion valve
Leakage of refrigerant from
heat sensor tube
Replace expansion valve
Temporary clogging of expansion valve caused by
freezing (Trouble by water in
refrigerating cycle)
Replace expansion valve, receiver, and drier, then evacuate refrigerating cycle thoroughly
Other
sections
4
Possible cause
Refrigerating
cycle
Air is not cooled well and
bubbles pass through sight
glass continuously
Insufficient refrigerant
Charge with refrigerant to
proper level.
Compressor
Shaft seals are stained with
oil clearly and refrigerant is
lost
Refrigerant leakage through
shaft seals
Replace compressor
Refrigerating
cycle
Pipe joints are stained with oil
clearly and refrigerant is lost
Leakage of gas from pipe
joints
Retighten joints or replace
piping
Clutch
When air conditioner switch is
turned ON, clutch is not engaged
Broken coil
Replace
Disconnection, defective wiring, or bad contact in wiring
parts (ground wire, fuse,
etc.)
Connect, repair, or replace
disconnected parts
Bad contact or defective operation of switches
Repair or replace
When air conditioner switch is
turned ON, rotor moves. If rotor is pushed with fingers, it
is attracted.
Too wide clearance between
rotor and stator
Repair or replace
Clutch slips during rotation
Low battery voltage
Charge battery
Clutch surface is stained with
oil
Remove oil
Layer short circuit in coil
Replace
Clutch
42-23
4
TESTING AND ADJUSTING
TROUBLESHOOTING
2.3 Check for refrigerant leakage
If refrigerant seems to be leaking as a result of the
basic inspection, check for leakage with the gas leak
tester according to the following procedure.
(1) Preliminary check
Connect the gauge manifold and check the condition of the refrigerant remaining in the refrigerating
cycle. Then, add new refrigerant, if necessary, to
heighten the pressure in the refrigerating cycle and
increase the accuracy of the gas leak check.
1 Read the gauge pressure while the compressor
is stopped. The ambient temperature must be
15°C or higher at this time.
2 If the gauge pressure is 0.4 MPa {4 kg/cm2} or
higher, start the inspection.
3 If the gauge pressure is below 0.4 MPa {4 kg/
cm2}, add new refrigerant to heighten the gauge
pressure above 0.4 MPa {4 kg/cm2}, then start
the inspection.
fl Perform the gas leak test in a place ventilated
well. An electric gas leak tester may react to
gasoline, diesel fuel, exhaust gas of a car, etc. If
it does so, it will misjudge.
fl Gas leaking from a pipe joint, etc. is blown away
by even a light wind. Accordingly, apply the
probe tip all around the joint.
Gas leak
tester
Probe
Probe
 Do not check for refrigerant leakage with a leak
detector of halide torch type. Since this detector detects gas leakage by utilizing reaction to
chlorine, it cannot detect refrigerant HFC-134a
which does not contain chlorine. In addition, it
decomposes HFC-134a into harmful matters. Accordingly, do not use it.
42-24
4
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
(2) Refrigerant leakage check procedure
Refrigerant leakage check in machine cab
Is oozing oil from each pipe joint detected
visually or by feeling with fingers?
YES
YES
Does leak tester react on
refrigerant?
Repair joint.
NO
Charge with specified quantity of
refrigerant and turn on air conditioner.
After vibrating devices and applying
pressure to them, check for leakage again.
Check connecting surfaces
for flaw and corrosion. If
they are normal, replace
O-ring and check again.
Refrigerant leakage check in operator's cab (from cooler unit) (with engine stopped)
Set blower to HI and ventilate unit with
fresh air for about 15 seconds.
Select circulated
air and leave for
about 10
minutes
(with blower
turned off).
Does leak
tester react on
refrigerant in
each air outlet?
YES
Check each
part to
specify
leaking part.
NO
Turn blower on for a moment (0.5
seconds) and off, then check each air
outlet for leakage again.
Air conditioner
42-25
4
TESTING AND ADJUSTING
TROUBLESHOOTING
[Reference]
• Check for refrigerant leakage by applying air pressure)
When it seems that little refrigerant is left in the refrigerating cycle, the leak check accuracy can be
increased by heightening the internal pressure of the refrigerating cycle with compressed nitrogen gas
or air.
1. Necessary tools
1 Air attachment: Special attachment to connect gauge manifold
2 Plug:
Plug to connect to utility piping of factory
(Select a proper plug on the market)
2. Check method
(1) Read the gauge pressure while the compressor is stopped. (The ambient temperature must be
15°C or above at this time.)
1 If the gauge pressure is about 0.2 – 0.4 MPa {2 – 4 kg/cm2}, apply air pressure and start the
inspection.
2 If the gauge pressure is below 0.2 MPa {2 kg/cm2}, add new refrigerant until the gauge pressure
rises above 0.4 MPa {4 kg/cm2}, then apply air pressure and start the inspection.
(2) Check for refrigerant leakage with a gas leak tester.
(3) After checking for refrigerant leakage, be sure to replace the mixture of the air and refrigerant with
new refrigerant.
<Method of applying air pressure>
1 Using the gauge, air attachment, and plug, connect an air compressor to the air conditioner
piping.
2 Start the air compressor to supply air.
fl Air pressure: Approx. 1.0 MPa {10 kg/cm2}
3 After applying air pressure, close the valves of
the gauge to keep the pressure in the air conditioner piping.
fl Be sure to drain water from the air compressor
used for applying air pressure. If it is drained,
little water is supplied to the refrigerating cycle.
fl The applied air pressure must be 1.0 MPa {10
kg/cm2} or less.
42-26
4
Air attachment
Plug
To air compressor
To air conditioner piping
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
3. Check for abnormal noise
(1) Since an abnormal noise is produced under various operating conditions, check the following.
• Is the abnormal noise produced even after the air conditioner is turned off?
• Is the abnormal noise produced only while the air conditioner is turned on?
• Is the abnormal noise produced at intervals, continuously, or just after the air conditioner is
turned on?
To specify the noise generating part, check the result of the examination by interview carefully.
(2) The general parts which can produce abnormal noises and the causes of those noises are as
follows.
V-belt
Looseness
Wear or damage of bearing
Magnetic clutch
Contact of stator and rotor
Production of noise
Foreign matter in motor
Blower motor
Insufficient tightening of blower
Looseness of bracket bolts
Defective valves
Compressor
Wear or damage or bearing
Misalignment
Defective tightening and installation of clamps
Piping
Improper safety gap
Air conditioner
42-27
4
TESTING AND ADJUSTING
TROUBLESHOOTING
[Reference]
• Identification of noise producing part
A noise producing part can be identified with a
stethoscope. How to check the abnormal noise from
the compressor with the stethoscope is explained
below, as an example.
If an abnormal noise is heard from around the compressor, you must see if it is produced by loosened
bracket bolts, auxiliary parts used to secure the compressor and belt, or internal parts of the compressor.
1 Apply the stethoscope to the auxiliary parts to
find out the noise source.
2 Apply the stethoscope to the compressor to see
if a noise similar to the above is heard. If the
similar noise is heard, the compressor may have
a trouble.
3 Generally, if the compressor has a trouble, it
produces an abnormal noise, regardless of the
engine speed.
42-28
4
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
4. Electric system
4.1 Inspection of electric system
See the circuit diagram (refer to the Shop Manual for each machine) and understand the electric circuit. Then,
check the connections of the electric parts systematically with a circuit tester, etc. The parts to be inspected
generally are as follows.
(1) Breakage of fuse
1) Referring to the wiring diagram, check the circuits where a fuse may be broken.
2) To check each functional part for internal short circuit, disconnect its connector.
(2) Bad contact of connector
1) Note that a functional part may not work because of bad contact of its connector.
2) Unstable operation and malfunction under vibration are caused by bad contact of a connector in many
cases.
(3) Defective grounding to chassis
Even if a ground wire seems firm, it may be insulated by paint film, rust, etc.
a PC400-7 is used as an example in the following explanation.
4.2 General block diagram (PC400-7) and circuit diagram
a Blower relay R30 and compressor relay R31 are installed to the side of the air conditioner unit (on the left
side of the unit).
Air conditioner
42-29
(6)
TESTING AND ADJUSTING
TROUBLESHOOTING
Circuit diagram related to air conditioner (PC400, 400LC-7, PC450, 450LC-7)
42-29-1
(6)
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
4.3 General drawing of air conditioner unit (PC400-7)
4.4 Self-diagnosis (PC400-7)
1. Turn the starting switch ON and turn switch (1)
of control panel P OFF.
2. Hold " " and "v" of temperature setting switch
(2) simultaneously for 3 seconds.
v
3. The error codes are displayed in (3).
4. Press " " or "v" of temperature setting switch
(2) to check all the error codes.
v
Display of error codes and failure modes
Display
Failure mode
E--
No failures
E11
Disconnection in internal air sensor
E12
Short circuit in internal air sensor
E15
Disconnection in water temperature sensor
E16
Short circuit in water temperature sensor
E17
Disconnection in sunlight sensor
E18
Short circuit in sunlight sensor
E43
Abnormality in air outlet damper
E44
Abnormality in air mix damper
E45
Abnormality in internal/external air damper
a The sunlight sensor is "S" at the top of the monitor panel.
Air conditioner
42-29-2
(6)
TESTING AND ADJUSTING
TROUBLESHOOTING
5. Replacement of parts
5.1 Interchangeability of air conditioner parts
The refrigerating cycle parts, functional parts closely related to them, and compressor oil for an air
conditioner which uses HFC134a (R134a) are not interchangeable with those for an air conditioner
which uses R12. Accordingly, different joints are used for each part of these air conditioners so that a
wrong part will not be used. Since the compressor oil, O-ring, etc. cannot be distinguished at a glance,
classify them into the HFC134a (R134a) group and the R12 group securely.
5.2 Connection of piping
(1) O-ring
•
•
•
If any piping or refrigerating cycle part is removed, be sure to use a new O-ring for HFC134a
(R134a).
When removing an O-ring, use a soft rod such as a toothpick so that the piping will not be
damaged.
When connecting the piping, apply compressor oil to the O-ring and tighten the adapter to the
specified torque.
(2) Tightening torque
Connector
Nut type
Tube size or
bolt size
Tightening torque
Nm {kgcm}
φ 8 pipe
12 – 15
{120 – 150}
D1/2 pipe
20 – 25
{200 – 250}
D5/8 pipe
30 – 35
{300 – 350}
M6 bolt (4T) of
receiver
4.0 – 7.0
{40 – 70}
M6 bolt (6T) other
than above
8.0 – 12
{80 – 120}
Nut type
Block joint
Block joint
42-30
4
Air conditioner
TESTING AND ADJUSTING
TROUBLESHOOTING
5.3 Adding compressor oil
(1) When replacing function part
When replacing a functional part (condenser, evaporator, etc.), add the following quantity of new compressor oil.
fl Add compressor oil for HFC134a (R134a). Supplementary oil is supplied in 40-cc cans.
<Quantity of supplementary compressor oil>
Replacement parts
Quantity of supplementary
compressor oil
(Reference value)
Compressor
Condenser
Evaporator
Receiver tank
Piping
80 cc
40 cc
40 cc
10 cc
10 cc
(per piece)
• Piston-type compressor (10P, 10PA series): ND-OIL8
Compressor oil
• Vane-type compressor (TV, SV series): ND-OIL9
(2) When replacing compressor
A new compressor is filled with oil necessary for
the refrigerating cycle. Accordingly, when replacing
an existing compressor, drain the excessive oil from
the new compressor.
New compressor
Compressor to
be replaced
fl Since the compressor oil for HFC134a (R134a)
absorbs moisture easily, seal the oil can immediately after supplying the oil.
5.4 Charging with refrigerant
After replacing a refrigerating cycle part, be sure to
perform the following work.
• Evacuation
• Charging with refrigerant
For the procedure for the above work, see Charging
with refrigerant.
Air conditioner
Drain
excessive oil
(A – B).
42-31
4
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
CHARGING WITH
REFRIGERANT
1. Precautions for charging with refrigerant ( Safety items)
(1) Only the appointed person must work.
Since high-pressure refrigerant is dangerous, only
the appointed person must handle it.
Appointed
person
If refrigerant liquid enters your eyes, the water in
the eyeballs is frozen and you may lose your eyesight. Accordingly, be sure to put on protective
goggles for safety while you are charging the air
conditioner with refrigerant. If the refrigerant liquid
is splashed over your hands, you may be frostbitten. Take care extremely. When installing and removing the service can and connecting and disconnecting the charging hoses, take care particularly.
Put on protective goggles.
(2) Put on protective goggles during work.
(3) Never work near your face.
Never install and remove the service can or connect
and disconnect the gauge manifold and compressor charging hoses near your face. If the refrigerant
liquid spouts out, you may be injured seriously.
 Actions to take when refrigerant enters your
eyes
Eye doctor
1) Do not rub your eyes with the hands or a handkerchief.
2) Immediately wash your eyes with clean water
for more than 15 minutes, then see a eye doctor.
42-32
4
Air conditioner
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
(4) Take care in handling the high-pressure
valve.
When charging the air conditioner with the refrigerant while the engine is running, never open the
high-pressure valve (HI) of the gauge manifold.
 If the high-pressure valve is opened by mistake,
the high-pressure gas may flow back into the
service can to burst.
Never
open this
valve.
(5) Never heat the service can.
If the service can is heated directly or put in a hot
water, the pressure in it rises to burst the can, and
that can injure you seriously.
1) If it is obliged to warm the service can in winter,
be sure to use water under 40°C.
2) Never put the service can in boiling water.
3) Do not put the service can on a hot engine, etc.
Hot
water
Below
40°C
(6) Do not leak the refrigerant gas near a fire
or a hot part of a stove, etc.
If the refrigerant gas comes in contact with the fire
or hot part, it is decomposed into harmful matters.
(7) Charge the refrigerating cycle with the refrigerant in a place ventilated well.
Do not leak!
(8) Never return the refrigerant to the service
can.
If the refrigerant in the refrigerating cycle is returned
to the service can, the can may burst, and that is
very dangerous.
(9) Do not apply pressure higher than 1 MPa
{10 kg/cm2} to the service can.
(10)Do not shake the service can strongly.
If the service can is not installed securely, it may
come off.
(11)When storing and handling the service can,
observe the following.
1) Store the service can away from children.
2) Do not put the service can in direct sunshine,
near a fire, or hot place.
3) Do not store the service can in a place where it
may be corroded. (Take care of humidity.)
4) Do not give a shock to the service can by dropping it, etc.
Air conditioner
42-33
4
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
2. Evacuation
If a refrigerating cycle part is replaced, the refrigerating cycle is opened to the atmosphere. Since air
always contains moisture, it must be dried. If there is any moisture in the refrigerating cycle, it may be
frozen in the small of the expansion valve and may rust the compressor valves, and that can cause a
trouble, even if it is little in quantity. Accordingly, the moisture in the refrigerating cycle must be
removed before the refrigerant is supplied.
To remove the moisture, the refrigerating cycle is evacuated with a vacuum pump to vaporize the
moisture. This work is called evacuation.
Check and repair of
connections
Charging with
refrigerant
Max. –0.1
MPa
(–750
mmHg)
Gauge pointer
returns
Check of airtightness with refrigerant
Leaving
for a
while
(5
minutes)
Check of indication
of gauge
10
minutes
Stop of evacuation
Start of evacuation
Check of
airtightness
Supply refrigerant in gas
state until gauge pressure
rises to 0.1 MPa (1 kg/cm2).
2.1 Connection of gauge manifold
(1) Connect the charging hoses to the high-pressure and low-pressure service valves.
fl Red hose — High-pressure side (Mark of H)
fl Blue hose — Low-pressure side (Mark of L)
(2) Connect the central charging hose (green) of
the gauge manifold to the vacuum pump.
 Take care not to mistake the high-pressure side

Valves
LO – Closed
HI – Closed
Low-pressure
valve (LO)
High-pressure
valve (HI)
and low-pressure side.
The service valves may be installed to the compressor.
Red
Blue
Green
Service valve on
low-pressure side
Vacuum pump
Service valve on
high-pressure side
42-34
4
Air conditioner
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
2.2 Evacuation
(1) Open the high-pressure valve (HI) and low-pressure valve (LO) of the gauge manifold.
(2) Turn on the vacuum pump to start evacuation
(for 10 minutes).
(3) After the low-pressure gauge reaches –0.1 MPa
{–750 mmHg}, close the high-pressure valve and
low-pressure valve of the gauge manifold and
turn off the vacuum pump.
Valves
LO – Open
HI – Open
fl If the vacuum pump is stopped before the valves
of the gauge manifold are closed, the atmosphere enters the refrigerating cycle.
Low-pressure
side
Pump is
turned on
High-pressure
side
2.3 Check of airtightness 1 (Check of
gauge pointer)
Leave the high-pressure valve and low-pressure
valve of the gauge manifold closed for a while (for
5 minutes) and check that the gauge pointer does
not return.
fl If the gauge pointer returns, the refrigerant is
leaking through some part. In this case, check
the pipe connections for looseness and repair
them, then evacuate and inspect again.
Valves
LO – Closed
HI – Closed
Leave for
5 minutes
Low-pressure gauge
Returns
Check and repair
pipe connections
Air conditioner
42-35
4
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
2.4 Check of airtightness 2
(Check with refrigerant)
Supply the refrigerant a little to the refrigerating
cycle, then check the airtightness with a gas leak
detector.
(1) Disconnect the charging hose (green) from the
vacuum pump and connect it to the service can.
For the method of installing the service can, see
“Service can valve (on page 42-9)”.
(2) Discharge the air from the charging hose (green).
1 Tighten the handle of the service can valve
to make a hole in the service can and open
the valve.
2 Push the valve of the gauge manifold to discharge the air from the hose with the refrigerant pressure until the refrigerant flows with
a hiss.
Valves
LO – Closed
HI – Closed
Open valve
Push valve
Blue
 At this time, keep both high-pressure valve and

low-pressure valve of the gauge manifold closed.
Take care that the refrigerant will not stick to
your hands. (You may be frostbitten.)
(3) Open the high-pressure valve of the gauge manifold and supply the refrigerant until the lowpressure gauge indicates 0.1 MPa {1 kg/cm2}.
(4) After supplying the refrigerant, close the highpressure valve.
(5) Check for refrigerant leakage carefully with the
gas leak detector.
If any part is leaking, repair it.
Green
Red
To service valve
Valves
LO – Closed
HI – Open
Service can
After supplying
refrigerant, close
high-pressure valve.
fl Be sure to use a detector for HFC134a (R134a)
to check for refrigerant leakage.
Valve: Open
Low-pressure
side
Service can
High-pressure
side
42-36
4
Air conditioner
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
3. Charging with refrigerant
After evacuating the refrigerating cycle, charge it with the refrigerant according to the following
procedure.
(1) Stop the engine and supply the refrigerant from the high-pressure side.
(2) Run the engine and supply the refrigerant from low-pressure side additionally.
Check for refrigerant
leakage
Check of quantity of
refrigerant
Supply from lowpressure side
Supply from highpressure side
Check of airtightness
Evacuation
Supply of
refrigerant
3.1 Supply from high-pressure side
(1) Stop the engine and open the high-pressure
valve of the gauge manifold and the service can
valve and supply about a can of the refrigerant.
 Never turn on the compressor at this time. If it


is turned on, the refrigerant flows back to burst
the hoses or service can, and that is very dangerous.
Do not turn on the compressor before charging
the refrigerating cycle with refrigerant. If it is
turned on, it may be seized.
Do not open the low-pressure valve of the gauge
manifold. If it is opened, the compressor may
compress the refrigerant liquid and may be broken.
(2) Close the high-pressure valve of the gauge manifold and the service can valve.
Valves
LO – Closed
HI – Open
After supplying
refrigerant, close
high-pressure valve.
Valve: Open
Blue
Red
Green
Service valve on
low-pressure side
Service can
Service valve on
high-pressure side
Air conditioner
42-37
4
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
3.2 Supply from low-pressure side (Additional supply)
(1) Check that the high-pressure valve of the gauge
manifold is closed.
(2) Set the machine under the following condition.
• Run the engine and open the cab door fully.
• Air conditioner switch ....... ON
• Temperature control lever ... Lowest temperature
• Blower switch ..................... HI
• Engine speed ...................... Approx. 1,500 rpm
(3) Open the low-pressure valve of the gauge manifold and the service can valve to supply the
refrigerant to the specified level.
(4) After supplying the refrigerant, close the lowpressure valve of the gauge manifold and the
service can valve and stop the engine.
 Never open the high-pressure valve (HI) of the

gauge manifold. If it is opened, the refrigerant
flows back to burst the service can or charging
hoses, and that is very dangerous.
Never hold the service upside down. If it is held
upside down, the refrigerant in liquid state is
sucked in and compressed by the compressor.
As a result, the compressor valves may be broken.
Erect the service can to supply refrigerant in
gas state.
High-pressure
valve: Closed
Note: If this valve is opened,
service can will burst
and injure you seriously.
Run engine at
1,500 rpm
(Lowest temperature)
Open cab
door fully.
Valves
LO – Open
HI – Closed
Low-pressure side
Temperature
control lever
Never open highpressure valve.
High-pressure side
Valve: Open
Blue
Red
Green
Low-pressure
side
Service can
High-pressure
side
42-38
4
Air conditioner
TESTING AND ADJUSTING
[Reference]
• Supplying refrigerant when ambient temperature is low
When the ambient temperature is low, the refrigerant may not be supplied quickly. In this case, warm
the service can in warm water below 40°C to
heighten the internal pressure of the can.
 Do not heat the service can in hot water or over
a fire. If it is heated so, it will burst and injure
you seriously. Be sure to use warm water below 40°C. (Check the temperature with a thermometer.)
CHARGING WITH REFRIGERANT
After supplying
refrigerant, close
this valve.
Valves
LO – Open
HI – Closed
Low-pressure
valve
High-pressure
valve
Valve: Open
fl When warming the service can in warm water,
do not submerge the service can valve in the
water. If it is submerged, moisture may enter
the refrigerating cycle.
fl Supplying refrigerant when ambient temperature is high
When the ambient temperature is high, cool the
condenser with an electric fan so that the refrigerant will be supplied quickly.
Air conditioner
Low-pressure
side
High-pressure
side
Warm water
below 40°C
42-39
4
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
3.3 Replacement of service can
If the service can becomes empty while the refrigerant is supplied from it, replace with new can according to the following procedure.
(1) Close the high-pressure valve and low-pressure
valve of the gauge manifold.
(2) Raise the service can valve needle and disc.
(3) Install a new service can to the service can valve.
(4) Discharge the air from the charging hose according to the following procedure.
1 Tighten the handle of the service can valve
to make a hole in the service can and open
the valve.
2 Push the valve of the gauge manifold to discharge the air from the hose with the refrigerant pressure until the refrigerant flows with
a hiss.
Handle
Hose adapter
Needle
Disc
Packing
Service can
Valves
LO – Closed
HI – Closed
 At this time, keep both high-pressure valve and
low-pressure valve of the gauge manifold closed.
 Take care that the refrigerant will not stick to
your hands. (You may be frostbitten.)
(5) Continue supplying the refrigerant.
Open valve
Push valve
Blue
Green
Red
To service valve
42-40
4
Service can
Air conditioner
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
4. Check of quantity of refrigerant
After supplying the refrigerant, check the quantity
of supplied refrigerant according to the following
procedure.
4.1 Check with gauge manifold
(1) Set the machine under the following condition.
• Door ................................. Full open
• Temperature control ...... Lowest temperature
• Blower speed .................. HI
• Circulated air/Fresh air
selector switch ................ Circulated air
• Engine speed .................. 1,500 rpm
fl Measure the quantity of the refrigerant while
the pressure on the high-pressure side is below
1.86 MPa {19 kg/cm2}.
If the ambient temperature is high (above 40°C)
and the pressure on the high-pressure side is
higher than 1.86 MPa {19 kg/cm2} under the specified judgment condition, perform the following
to lower the pressure below 1.86 MPa {19 kg/
cm2}.
1 Close the door fully and set the blower speed
to LO.
2 Move the machine indoors or into the shade.
(2) Read the gauge manifold.
When normal
Pressure on low-pressure side:
0.15 – 0.25 MPa {1.5 – 2.0 kg/cm2}
Pressure on high-pressure side:
1.37 – 1.57 MPa {14 – 16 kg/cm2}
Low-pressure side
High-pressure side
fl The values indicated by the gauge manifold may
vary more or less with the condition.
fl Too much refrigerant in the refrigerating cycle
can cause insufficient cooling capacity, overheating, etc.
Air conditioner
42-41
4
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
4.2 Check with sight glass (Simple inspection)
(1) Set the machine under the following condition.
• Door ................................. Full open
• Temperature control ...... Lowest temperature
• Blower speed .................. HI
• Circulated air/Fresh air
selector switch ................ Circulated air
• Engine speed .................. 1,500 rpm
(2) Under the above condition, check the refrigerant flow in the sight glass.
<Judgment>
fl Proper:
Little bubbles are seen.
If the engine speed is
increased from idling to
1,500 rpm, the bubbles
disappear and the refrigerant becomes transparent.
fl Too much refrigerant: No bubbles are seen. In
this case, both pressures
on the high-pressure
side and low-pressure
side are high and the air
in the cab is not cooled
well.
fl Insufficient refrigerant: Bubbles pass the sight
glass continuously.
42-42
4
Too much
refrigerant
Proper
Insufficient
refrigerant
Sight glass
Air conditioner
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
4.3 Disconnection of gauge manifold
After finishing supplying the refrigerant, stop the
engine and disconnect the charging hoses according to the following procedure.
(1) Disconnect the charging hose (quick joint) on
the low-pressure side from the service valve
quickly.
(2) Before disconnecting the charging hose on the
high-pressure side, wait until the value indicated
by the high-pressure gauge lowers sufficiently
(to 1 MPa {10 kg/cm2} or below).
(3) Disconnect the charging hose on the high-pressure (red) side similarly to the one on the lowpressure side.
Valves
LO – Closed
HI – Closed
Leave charging hose
on high-pressure
side until value
indicated by highpressure gauge
lowers sufficiently,
then disconnect it.
Valve: Closed
Blue
Red
Green
Service valve on
low-pressure side
Service can
Service valve on
high-pressure side
 Perform the above work as quickly as you can

to minimize the leakage of the refrigerant. When
disconnecting the high-pressure charging hose,
wait until the gauge indicates 1 MPa {10 kg/
cm2} or less, since compressor oil may spout
out together with refrigerant, then disconnect
it quickly, covering it with a cloth so that the oil
will not be splashed.
Take care extremely that the refrigerant will
not stick to your hands or enter your eyes. (Put
on safety goggles.)
Air conditioner
42-43
4
TESTING AND ADJUSTING
PERIODIC INSPECTION AND MAINTENANCE
PERIODIC INSPECTION AND MAINTENANCE
1. Inspection and maintenance items
You are required to inspect and maintain each air conditioner properly to use it always under the best condition.
Generally, perform the following inspections and maintenance for the air conditioner.
Inspection/Maintenance items
Inspection/Maintenance period
6 months
12 months
Refrigerant (Gas) (Sight glass)
Quantity
q
q
Condenser
Clogging of fins
q
q
Compressor
Operating condition
Air filters (for internal/external air)
Clogging
Belt
Damage and tension
Blower motor
Operating condition and abnormal sound
q
Control mechanism
Operating condition
q
Mounting parts and piping
Mounting condition, looseness of tightening
parts and connections, gas leakage, and
damage
q
q (3 months)
q
q
q
q
a The manufacturer (DENSO CO., LTD.) recommends replacing the receiver drier and blower motor every 4
years.
1.1 Inspection and cleaning of condenser
fins
a For PC400-7
Open the engine right side cover and clean
condenser fins (1) with compressed air or
water.
See Operation manual, Inspection and
maintenance, 500-hour maintenance
1.2 Cleaning of air filter (Internal/External air filters)
a For PC400-7
• Internal air filter: E (Left rear of seat)
• External air filter: F (Open cover at left rear
of operator's cab and take out filter)
Clean the filter with compressed air or neutral detergent
See Operation manual, Inspection and
maintenance, 500-hour maintenance
42-44
(6)
Air conditioner
TESTING AND ADJUSTING
PERIODIC INSPECTION AND MAINTENANCE
2. Check of quantity of refrigerant
(Check with sight glass)
(1) Set the machine under the following condition.
• Door ................................. Full open
• Temperature control ...... Lowest temperature
• Blower speed .................. HI
• Circulated air/Fresh air
selector switch ................ Circulated air
• Engine speed .................. 1,500 rpm
• Air conditioner ................ ON
(2) Check the condition of the refrigerant in the sight
glass.
<Judgment>
fl Proper:
Little bubbles are seen.
If the engine speed is
increased from idling to
1,500 rpm, the bubbles
disappear and the refrigerant becomes transparent.
fl Too much refrigerant: No bubbles are seen. In
this case, both pressures
on the high-pressure
side and low-pressure
side are high and the air
in the cab is not cooled
well.
fl Insufficient refrigerant: Bubbles pass the sight
glass continuously.
Air conditioner
Too much
refrigerant
Proper
Insufficient
refrigerant
Sight glass
42-45
4
TESTING AND ADJUSTING
PERIODIC INSPECTION AND MAINTENANCE
3. Inspection of functional parts
(1) Inspection of control mechanism
Operate the levers and switches on the control panel
to see if they work smoothly and securely. If any
part is troubled, adjust or repair it.
Sm
oot
h
(2) Inspection of belt
Check the belt for damage. If it is damaged, replace
it.
In addition, check the belt tension (See the Shop
Manual for each machine). If it is out of the standard range, adjust it.
Inspection of idling-up speed
Check the idling-up speed. (See the Shop Manual
for each machine.) If it is out of the standard range,
adjust it.
(3) Inspection of compressor and magnetic
clutch
Turn the air conditioner switch on to see if the magnetic clutch is turned on. Check that magnetic clutch
and compressor for abnormal noise. If any abnormal noise is produced, adjust or repair.
42-46
4
Air conditioner
TESTING AND ADJUSTING
PERIODIC INSPECTION AND MAINTENANCE
(4) Inspection of idler pulley
Repair me,
please!
Check the idler pulley for abnormal noise. If any
abnormal noise is produced, adjust or repair.
(5) Cleaning of condenser
If much soil and dirt stick to the condenser fins, the
cooling capacity is lowered. Accordingly, wash away
the soil and dirt with water. If the fins are dirty
extremely, clean them with a soft brush.
(6) Inspection of each fitting part
Check each fitting part (mounting bolt, screw, nut,
etc.) for looseness. If any part is loosened, retighten
it.
Check the pipe joints for oil sticking to them. If any
joint is coated with oil, the refrigerant may be leaking through it. In this case, check the joint with a
gas leak detector. If the refrigerant is leaking, repair
or replace the joint.
Air conditioner
Inspect with gas
leak detector!
(7) Inspection of pipe joints
42-47
4
STRUCTURE AND FUNCTION
STRUCTURE AND FUNCTION
TAKAHASHI WORKS
Outline ....................................................................................................................................................... 51- 2
Refrigerating cycle system diagram .......................................................................................................... 51- 4
Compressor ............................................................................................................................................... 51- 6
Condenser ................................................................................................................................................. 51- 9
Receiver drier ............................................................................................................................................ 51- 9
Air conditioner unit..................................................................................................................................... 51- 10
• Air circuit...................................................................................................................................................51- 11
• Evaporator............................................................................................................................................... 51- 12
• Expansion valve ...................................................................................................................................... 51- 13
• High and low pressure switch.................................................................................................................. 51- 14
• Heater core.............................................................................................................................................. 51- 15
• Water valve ............................................................................................................................................. 51- 15
• Temperature regulation amplifier............................................................................................................. 51- 16
• Blower motor ........................................................................................................................................... 51- 16
• Resistor ................................................................................................................................................... 51- 16
• Damper actuator...................................................................................................................................... 51- 17
• Relay ....................................................................................................................................................... 51- 17
• Internal air filter and external air filter ...................................................................................................... 51- 17
Air conditioner
51-1
(5)
(5)
STRUCTURE AND FUNCTION
OUTLINE
OUTLINE
Reference: The following figure shows PC100-6 as an example.
4. Receiver drier
5. Air conditioner unit
6. Duct
1. Control switch
2. Compressor
3. Condenser
•
PC100-6 is equipped with an air conditioner of
full heat type, in which the cooler and heater are
arranged in series against air flow and made in 1
unit.
•
The compressor is of vane rotary type. It is
driven by the engine through V-belt to compress
refrigerant gas of low pressure and lower temperature. As a result, the pressure and temperature of the refrigerant gas are heightened, and
then the refrigerant gas is sent to the condenser.
51-2
(5)
(5)
•
The air conditioner unit is installed to the rear of
the operator's seat in the cabin. The air cooled
or heated in this unit is sent through the ducts to
the air blow grilles at the rear and right of the
operator's seat.
•
The air temperature, air outlet, selection of external or internal air, and strength of air flow are
selected with the air conditioner switches on the
control panel.
Air conditioner
STRUCTURE AND FUNCTION
OUTLINE
Layout of air conditioner parts in cab
1. Grille for rear FACE
(Air flow direction: Changeable vertically and horizontally)
2. Heater core
3. Evaporator
4. EXTERNAL/INTERNAL air changeover damper
5. External air filter
6. Internal air filter
7. Blower motor
8. Refrigerant inlet (M16 x 1.5)
9. Refrigerant outlet (M22 x 1.5)
10. Hot water inlet
11. Hot water outlet
12. Selector damper
13. FOOT grill
(Air flow direction: Fixed)
Air conditioner
14. DEFROSTER grill
(Air flow direction: Changeable vertically and horizontally)
15. FOOT-DEFROSTER selector lever
(Operated manually)
16. Right side FACE grill
(Air flow direction: Changeable vertically and horizontally)
17. FACE control wire
18. Control panel
19. Chassis-side wiring harness
a.
b.
c.
d.
e.
f.
g.
FACE
FACE
External air inlet
Internal air inlet
FOOT
DEFROSTER
FACE
51-3
(5)
(5)
STRUCTURE AND FUNCTION
REFRIGERATING CYCLE CIRCUIT DIAGRAM
REFRIGERATING CYCLE CIRCUIT DIAGRAM
51-4
(5)
(5)
Air conditioner
STRUCTURE AND FUNCTION
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Air outlet
Heater core
Evaporator
Blower motor
Expansion valve
High and low pressure switch
Relief valve
Liquid eye
Magnetic clutch
Thermal switch
Filter
Desiccating agent
Receiver drier
Condenser
Electric cooling fan
Compressor
Filter
Filter
Heat sensor tube
Thermistor
Water valve
Control switch
Air outlet
Air conditioner
REFRIGERATING CYCLE CIRCUIT DIAGRAM
A.
B.
C.
D.
Evaporation
Expansion
Compression
Condensation
a.
b.
c.
d.
Charged with gas
Liquid of low temperature and low pressure
Temperature: 50 - 60fC
Temperature: 8 - 15fC
Pressure: 0.1 - 0.2 MPa {1 - 2 kg/cm2}
Liquid of high temperature and high pressure
Suction
Discharge
Gas of high temperature and high pressure
Temperature: 50 - 60fC
Liquid of high temperature and high pressure
Temperature: 80 - 120fC
(Reference value for normal operation)
Pressure: 1.37 - 1.57 MPa {14 - 16 kg/cm2}
(Reference value for normal operation)
Gas of low temperature and low pressure
External air
Internal air
Hot water OUT
Hot water IN
e.
f.
g.
h.
i.
j.
k.
l.
m.
n.
o.
p.
51-5
(5)
(5)
STRUCTURE AND FUNCTION
COMPRESSOR
COMPRESSOR
The rotation of the engine is transmitted through the
belt to the clutch, which is turned ON and OFF by
the temperature regulator thermostat. Then, the
rotor of the compressor coupled directly with the
clutch is rotated. The rotor has 5 vanes. As the
rotor rotates, the vanes slide on the inside wall of the
cylinder to compress and suck the refrigerant gas
repeatedly.
Function
•
The compressor sucks the refrigerant gas of low
pressure and low temperature evaporated in the
evaporator and compresses it. The pressure
and temperature of the compressed refrigerant
gas become high, and then the refrigerant gas is
discharged into the condenser. The refrigerant
gas is circulated in the refrigerating cycle. The
temperature and pressure of the refrigerant gas
are heightened by the compressor, and then the
refrigerant gas is cooled and liquefied in the condenser
51-6
(5)
(5)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
a.
b.
Oil separator
Front head
Mechanical seal
Clutch
Front side block
Case
Rear side block
Rotor
Cylinder
Vane
Discharge opening
Suction opening
Air conditioner
STRUCTURE AND FUNCTION
COMPRESSOR
Operation processes of compressor
(1) Starting suction
Suction of the refrigerant gas starts when vane
A passes by suction opening (1) (White arrow).
As the rotor rotates, the space (hatched part)
formed by vanes A and E, rotor, and cylinder is
increased to continue sucking the refrigerant
gas.
(2) Finishing suction (Closing) - Starting compression
Suction finishes when vane E passes by suction
opening (1).
The hatched part in the figure at this time is the
maximum space and compression starts at this
point.
(3) Compression - Discharge
The compressed refrigerant gas pushes up the
lead valve installed at discharge opening (2) and
goes out (Black arrows).
Just after this time, vane A starts suction through
suction opening (1) on the opposite side.
s As explained above, each compression space
performs the cycle of suction, compression, and
discharge 2 times in 1 turn. Accordingly, the
compressor performs 10 cycles in 1 turn.
Air conditioner
51-7
(5)
(5)
STRUCTURE AND FUNCTION
COMPRESSOR
Relief valve (Installed to compressor)
When the high pressure in a car air conditioner for
R12 becomes abnormally, a melt bolt is melted to
discharge the refrigerant into the atmosphere to
protect the air conditioner cycle. In this case, all
the refrigerant in the cycle is discharged.
On the other hand, a car air conditioner for R134a
employs a pressure relief valve instead of the melt
bolt to minimize discharge of the refrigerant when
abnormally high pressure is generated.
The refrigerant discharge route made when the
relief valve operates is shown in the figure.
s Operating pressure
Start of blowing: 3.4 MPa {35 kg/cm2}
Stop of blowing: 2.9 MPa {30 kg/cm2}
Thermal switch (Installed to compressor)
This switch is installed near the discharge port of
the compressor. It turns the power for the clutch
OFF when the temperature of the compressor
becomes abnormally high. When the temperature
of the compressor lowers to the normal level, the
thermal switch turns the power for the clutch ON
again.
s Operating temperature
ON : 95fC
OFF: 140fC
1.
2.
3.
4.
Wiring harness
Diaphragm bimetal
Compressor
Contact
51-8
(5)
(5)
Air conditioner
CONDENSER ANR RECEIVER
DRIER
CONDENSER
STRUCTURE AND FUNCTION
CONDENSER
The refrigerant of high pressure and high temperature sent from the compressor to the condenser is
cooled and liquefied with a cooling fan.
The condenser consists of aluminum tubes and corrugated fins.
RECEIVER DRIER
The liquefied refrigerant of high pressure and high
temperature sent from the condenser is stored in the
receiver drier. Even if bubbles are mixed in the liquefied refrigerant, depending on the radiating condition of the condenser, only liquefied refrigerant is
sent to the expansion valve. The filter and desiccating agent remove the dirt and water in the cycle.
The operator can see the flow of the refrigerant
through the liquid eye at the top of the receiver drier
Air conditioner
1.
2.
a.
b.
c.
d.
Louver fin
Tube made by extrusion
Passage of refrigerant gas
Passage of air
Inlet (M20 x 1.5 with O-ring)
Outlet (M16 x 1.5 with O-ring)
to judge the quantity of the refrigerant.
1. Desiccating agent
2. Filter
3. Liquid eye
4. Thread size: M16 x 1.5
a. Flow of liquefied refrigerant from condenser
b. Stored liquefied refrigerant
c. Connection to air conditioner unit
51-9
(5)
(5)
STRUCTURE AND FUNCTION
AIR CONDITIONER UNIT
AIR CONDITIONER UNIT
1.
2.
3.
4.
5.
Drain pan
Damper case
Heater core
Evaporator
Blower motor
6.
7.
8.
9.
EXTERNAL/INTERNAL air changeover damper
External air filter
Internal air filter
Cover
The temperature in the cab is controlled through the
respective heat exchangers of the refrigerant gas for
cooling and the hot water for heating. The external
or internal air is sent by the blower in the unit
through the filters to the air outlets after divided by
the selector damper.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Upper air outlet
External air suction opening
Internal air suction opening
Refrigerant gas inlet (M16 x 1.5 with O-ring)
Refrigerant gas outlet (M22 x 1.5 with O-ring)
Hot water inlet
Hot water outlet
Side air outlet
Selector duct actuator
51-10
(5)
Air conditioner
STRUCTURE AND FUNCTION
AIR CONDITIONER UNIT
Air circuit
1. External/Internal air changeover damper (Operated with actuator)
2. Fan
3. Evaporator
4. Heater core
5. Damper (Operated with actuator)
6. Blower motor
a.
b.
c.
d.
External air
Internal air
Side air outlet
Upper air outlet
Air conditioner
51-11
(5)
STRUCTURE AND FUNCTION
AIR CONDITIONER UNIT
Evaporator
The fins of the evaporator are cooled by the lowtemperature refrigerant mist sent through the expansion valve. Then, the fins cool and dry the warm air
sent by the blower motor.
1.
2.
3.
4.
Refrigerant inlet
Refrigerant outlet
Slit fins
Refrigerant passage holes
a. Air (Room temperature)
b. Air (Cooled)
c. Plate thickness: 5 mm
51-12
(5)
Air conditioner
STRUCTURE AND FUNCTION
AIR CONDITIONER UNIT
Expansion valve
The refrigerant liquid of high pressure and high temperature sent from the receiver drier is sprayed
through the expansion valve. As a result, the refrigerant becomes mist of low pressure and low temperature. The closing ratio of the expansion valve is
changed according to the thermal load of the cab to
control the refrigerant flow rate in the refrigerating
cycle automatically.
1.
2.
3.
4.
5.
6.
7.
8.
Diaphragm
Valve stem
Adjustment screw
Adjustment spring
Ball
P2
Evaporator
Heat sensor tube (to sense gas temperature on
cooler outlet side)
9. Capillary tube
a. Refrigerant liquid inlet
b. To compressor
c. Volume changes according to temperature
(Filled with gas).
Air conditioner
51-13
(5)
STRUCTURE AND FUNCTION
AIR CONDITIONER UNIT
High and low pressure switch
This switch is installed to the liquid tube. When
abnormally low or high pressure is generated in the
air conditioner cycle, this switch turns the compressor
OFF to protect the parts in the air conditioner cycle.
1. Spring
2. Stopper
3. Contact
4. Plate
5. Belleville spring
6. Diaphragm
7. Pin
8. Terminal
a. Refrigerant pressure
Operation
• When pressure is normal
When the refrigerant pressure is higher than
0.21 MPa {2.1 kg/cm2}, its force is larger than
the force of spring (2). As a result, diaphragm
(6) is deformed and plate (4) is pushed up to
close contact (3).
•
When pressure is abnormally low
When the refrigerant pressure is lower than 0.20
MPa {2.0 kg/cm2}, plate (4) is pushed down by
the force of spring (2) and contact (3) is opened.
•
When pressure is abnormally high
When the refrigerant pressure is lower than 3.1
MPa {32 kg/cm2}, diaphragm (6) is deflected and
belleville spring (5) buckles back. As a result,
the contact is pushed up and opened through
pin (7).
51-14
(5)
Air conditioner
STRUCTURE AND FUNCTION
AIR CONDITIONER UNIT
Heater core
The hot water from the engine flows into the heater
core to warm the air flowing through the heater core.
The temperature of the air flowing through the
heater core can be controlled by adjusting the hot
water flow rate with the water valve.
1.
2.
3.
4.
Hot water inlet pipe (φ14 mm)
Hot water outlet pipe (φ14 mm)
Hot water passage
Air passage
a. Hot water inlet
b. Hot water outlet
Water valve
The water valve controls the flow rate of the hot
water flowing from the engine to the heater core
according to the command from the control switch.
It is driven by the motor actuator.
1.
2.
3.
4.
Rod
Valve
Hot water inlet pipe (φ16 mm)
Hot water outlet pipe (φ16 mm)
a. Driven by motor
b. Hot water inlet
c. Hot water outlet
Air conditioner
51-15
(5)
STRUCTURE AND FUNCTION
AIR CONDITIONER UNIT
Temperature regulation amplifier
There are relays and a temperature regulation board
in this amplifier unit. The thermistor senses hot air
from the evaporator and the thermal amplifier compares the hot air temperature with the value set with
the control knob and turns the compressor ON and
OFF.
The thermistor is also used to prevent freezing of the
evaporator.
1. Thermistor
a. Connected to variable resistor or fixed resistor
Blower motor
The blower sucks external or internal air and sends
it to the evaporator and heater core to exchange
heat. The heat-exchanged air is directed by the
damper and sent through the duct to the air outlet
grille. The blower motor speed is set to 3 levels by
means of resistor according to the fan switch which
is set manually.
1. Scroll
2. Motor
3. Sirocco fan
Resistor
This resistor is used to lower the blower motor current, or the blower motor speed, to 3 levels.
51-16
(5)
1. Resistor (Low)
2. Resistor (Mid)
3. Temperature fuse (Turned OFF at 76fC, not reset
automatically)
Air conditioner
STRUCTURE AND FUNCTION
AIR CONDITIONER UNIT
Damper actuator
This motor damper actuator sets the selector
damper to the displayed position of the control panel
switch. The damper is rotated and sets to 3 positions through reduction gears.
Relay
This relay turns a large current ON and OFF according to the signals from the switch and temperature
regulation amplifier.
1. Output side
2. Signal input
3. Ground
4. Input side
Internal air filter and external air filter
If dust and dirt sticks to the heat exchanger, the cooling and heating capacity is reduced. To prevent this
trouble, filters are installed to the internal and external air suction openings of the air conditioner unit to
remove the dust and dirt from the air.
1. External air filter
2. Internal air filter
Air conditioner
51-17
(5)
STRUCTURE AND FUNCTION
51-18
(5)
AIR CONDITIONER UNIT
Air conditioner
TESTING AND ADJUSTING
TESTING AND ADJUSTING
TAKAHASHI WORKS
List of tools for testing, adjusting, and troubleshooting............................................................................ 52-
2
Precautions for measuring refrigerant pressure, charging with refrigerant, and discharging refrigerant. 52-
3
Testing quantity of refrigerant .................................................................................................................. 52-
6
Procedure for charging with refrigerant ................................................................................................... 52- 10
Procedure for replacing service can ........................................................................................................ 52- 13
Procedure for discharging refrigerant ...................................................................................................... 52- 14
Cleaning internal and external air filters .................................................................................................. 52- 16
Troubleshooting ....................................................................................................................................... 52- 101
Air conditioner
52-1
(5)
(5)
LIST OF TOOLS FOR TESTING, ADJUSTING, AND TROUBLELIST OF TOOLS
FOR TESTING, ADJUSTING, AND TROUBLESHOOTING
SHOOTING
TESTING AND ADJUSTING
LIST OF TOOLS FOR TESTING, ADJUSTING, AND TROUBLESHOOTING
Testing and adjusting
item
Symbol
Part No.
Part name
1 799-703-1200 Service tool kit
799-703-1100 Vacuum pump
799-703-1111 Vacuum pump
Measuring refrigerant
pressure in air condiN
tioner, charging with
refrigerant, and discharging refrigerant
2 799-703-1121 Vacuum pump
52-2
(6)
(5)
O
For new refrigerant R134a
For new refrigerant R134a in Japan
(100 V)
For new refrigerant R134a in overseas countries (220 V)
For new refrigerant R134a in overseas countries (240 V)
799-702-1320 Vacuum pump
For Freon R12 in USA (115 V)
799-702-1330 Vacuum pump
For Freon R12 in overseas countries (220 V)
3 799-703-1300 Adapter
Leakage of refrigerant
Remarks
799-703-1400 Gas leak tester
For use of vacuum pump for R12
For countries other than USA
Air conditioner
PRECAUTIONS FOR MEASURING REFRIGERANT PRESSURE, CHARGTESTING AND ADJUSTING PRECAUTIONS
FOR MEASURING
CHARGING
ING WITH REFRIGERANT,
ANDREFRIGERANT
DISCHARGINGPRESSURE,
REFRIGERANT
PRECAUTIONS FOR MEASURING REFRIGERANT PRESSURE,
CHARGING WITH REFRIGERANT, AND DISCHARGING REFRIGERANT
1. Precautions for using service tool kit N1 for
car air conditioner
• The joints of service tool kit N1 for R134a car
air conditioner are different from those for
the other refrigerants.
1.
2.
3.
4.
5.
Gauge manifold
High-pressure charging hose (Red)
Quick joint (Hi) [Large diameter]
Center charging hose (Green)
Quick joint (Lo) [Small diameter]
Air conditioner
s Use R134a service tool kit N1 for R134a car
air conditioner.
s Do not use R134a service tool kit N1 for R12
car air conditioner.
s Do not use R12 service tool kit.
6. Low-pressure charging hose (Blue)
7. Service can valve
8. Service can valve joint
a. Since the threads are course and loosened easily, take care.
52-3
(5)
(5)
PRECAUTIONS FOR MEASURING REFRIGERANT PRESSURE, CHARGTESTING AND ADJUSTING PRECAUTIONS
FOR MEASURING
CHARGING
ING WITH REFRIGERANT,
ANDREFRIGERANT
DISCHARGINGPRESSURE,
REFRIGERANT
2. Precautions for connecting quick joint
• Press the quick joint against the charging
valve and push in part A securely until it
clicks.
Completion of connection
s When pressing the joint to connect it, take
care not to bend the piping.
s If sleeve (1) has moved without connecting to
the charging valve, return it to the set position
and connect again.
s If any refrigerant is left in the charging hose,
the joint may not be connected easily. In this
case, release the residual pressure in the
hose.
3. Precautions for disconnecting quick joint
• Securing part A of the quick joint, slide part
B (sleeve) up.
Completion of disconnection
s After disconnecting the quick joint, install the
cap to the charging valve.
Precautions for handling R134a charging valve
• When operating valve (4) of R134a charging
valve (6), observe the following.
s When discharging the refrigerant, be sure to
use special quick joint (2).
s Never push in valve (4) with screwdriver (3),
etc. to discharge the refrigerant. If it is pushed
in strongly (with force of 2.4N {3 kg} or larger),
spring (5) may come off and refrigerant may
leak.
52-4
(5)
(5)
Air conditioner
PRECAUTIONS FOR MEASURING REFRIGERANT PRESSURE, CHARGTESTING AND ADJUSTING PRECAUTIONS
FOR MEASURING
CHARGING
ING WITH REFRIGERANT,
ANDREFRIGERANT
DISCHARGINGPRESSURE,
REFRIGERANT
5. Precautions for using vacuum pump
• If R12 vacuum pump N2 is equipped with
vacuum pump adapter N3 additionally, it can
be used for both R134a car air conditioner
and R12 car air conditioner.
Abnormal
indication
by gauge
Checking and
repairing joints
Charging with
refrigerant
Checking for refrigerant leakage
Leaving
Charging with
refrigerant
Negative
pressure :
Min100kPa
{750mmHg}
5 min
Checking
airtightness
30 min
Stopping
evacuation
Precautions for charging with refrigerant and
checking for refrigerant leakage
• Charge with the refrigerant by the conventional method.
Starting
evacuation
6.
(*1)
Charge with refrigerant gas up to gauge pressure of
0.1 MPa {1 kg/cm2}.
s When evacuating, connect the vacuum pump
to the quick joints on both high-pressure and
low-pressure sides. If the pump is not connected to both sides, the atmosphere enters
through the unconnected joint. (The check
valve of the quick joint cannot keep vacuum.)
s Before stopping the vacuum pump (turning the
switch OFF) after evacuating, close the gauge
(
manifold.
)
If the vacuum pump is stopped before the
gauge manifold is closed, the evacuated air
conditioner circuit is opened to the atmosphere.
s Precautions for checking refrigerant leakage (*1)
When checking refrigerant leakage from the
R134a car air conditioner, be sure to use R134a
gas leak tester O. Do not use the R12 gas leak
tester, since its sensitivity is too low.
a. When using the R12 vacuum pump, use adapter N3.
b. Close the gauge manifold before turning the switch
OFF.
Air conditioner
52-5
(5)
(5)
TESTING AND ADJUSTING
TESTING QUANTITY OF REFRIGERANT
TESTING QUANTITY OF REFRIGERANT
1. Visual inspection (Inspection through liquid eye)
k If the refrigerant liquid enters your eyes or
sticks to your hand, you may lose your eyes or
your hand skin may be frozen. Accordingly, do
not loosen a refrigerant circuit part.
• Test the quantity of the refrigerant while the
compressor is turned ON under the condition
in Table 1.
s When the compressor is turned OFF, bubbles are made even if the quantity of the
refrigerant is proper. Accordingly, check
that the compressor is turned ON when
testing the quantity of the refrigerant.
Table 1
Item
Condition
Door
Open full
Temperature control
Max.
Blower speed
Hi
External/Internal air
Internal
Engine speed
1,500rpm
Air conditioner switch
ON
s Judge the quantity of the refrigerant while the
pressure on the high pressure side is below
1.9MPa {19kg/cm2}.
s When the ambient temperature is high (above
40fC), if the pressure on the high pressure
side is higher above 1.9MPa {19kg/cm2}
under the judging condition, lower it below
1.9MPa {19kg/cm2} by the following method.
1. Close the door fully and set the blower speed
to Lo.
2. Test indoors or under a shade.
52-6
(5)
(5)
Air conditioner
TESTING AND ADJUSTING
TESTING QUANTITY OF REFRIGERANT
[Judgment]
Check table for quantity of refrigerant
Condition of
air conditioner
Normal
High-pressure tube
is hot and low-presTemperature of high
sure tube is cold.
and low pressure
Temperature differtubes
ence between them
is clear.
Condition of liquid
eye
Almost transparent.
Even if some bubbles are flowing, they
disappear when
engine speed is
increased or
decreased.
See Fig. a.
Abnormal
High-pressure tube
is warm and lowpressure tube is
cool. Temperature
difference between
them is not so clear.
There is little temperature difference
between high-pressure tube and lowpressure tube.
Bubbles flow conFog-like thing flows
stantly. Transparent. slightly.
White bubbles may
flow.
High-pressure tube
is hot and low-pressure tube is cool.
There is some temperature difference
between them.
Even if fan is set to
Hi (with doors
closed) while engine
is running idle, no
bubbles flow.
See Fig. b.
See Fig. c.
See Fig. d.
Condition of pipe
joints
Normal
Some parts are
stained with oil.
Some parts are
stained with oil
badly.
Normal
Condition of this air
conditioner
Quantity of refrigerant is proper.
Refrigerant may be
leaking a little.
Almost all refrigerant has leaked.
Quantity of refrigerant is too much.
Note that the contents of the above table change a little during the very cold season and very hot season.
Generally, bubbles are made easily in the very hot season and are not made easily (the refrigerant becomes transparent) in
the very cold season.
1. Liquid eye
2. Receiver drier
Air conditioner
52-7
(5)
(5)
TESTING AND ADJUSTING
TESTING QUANTITY OF REFRIGERANT
2. Measuring refrigerant pressure
kTake care that the refrigerant will not stick to
your hand.
k Put on protective goggles to prevent the refrigerant from entering your eyes.
1) Stop the engine and install service tool kit N1.
s Close the high-pressure valve and lowpressure valve of the gauge manifold.
s Connect blue hose (1) to the low-pressure
piping and red hose (2) to the high-pressure piping.
2) Release air from service tool kit N1.
i) Open the high-pressure valve gradually.
When the refrigerant comes out of the
green charge hose with a hiss, close the
high-pressure valve.
ii) Open the low-pressure valve gradually.
When the refrigerant comes out of the
green charge hose with a hiss, close the
low-pressure valve.
3) While the compressor is turned ON, measure
the refrigerant pressure and air conditioner suction temperature under the condition in Table 2.
s If the compressor is turned OFF, the
refrigerant pressure lowers extremely.
Accordingly, turn the compressor ON
when measuring the refrigerant pressure.
Table 2
Item
Condition
Door
Open full
Temperature control
Max.
Blower speed
Hi
External/Internal air
Internal
Engine speed
1,500rpm
Air conditioner switch
ON
s Note that the proper refrigerant pressure depends
on the air conditioner suction temperature.
Air conditioner refrigerant pressure standard
Air conditioner suc- High-pressure gauge prestion temperature(fC)
sure(MPa{kg/cm2})
52-8
(5)
(5)
15
1.03-1.32 {10.5-13.5}
20
1.17-1.47 {12.0-15.0}
25
1.32-1.62 {13.5-16.5}
30
1.47-1.77 {15.0-18.0}
35
1.62-1.91 {16.5-19.5}
a.
b.
c.
d.
e.
Quantity of refrigerant is too much
Quantity of refrigerant is proper
Quantity of refrigerant is insufficient
Air conditioner suction temperature
High-pressure gauge pressure
Air conditioner
TESTING AND ADJUSTING
TESTING QUANTITY OF REFRIGERANT
[Reference]
When the air conditioner suction temperature is in
the normal range of 30-35fC, the gauge pressure
becomes as shown in Table 3.
Table 3
<Gauge pressure indicated under normal condition>
Pressure on low
0.15-0.25MPa{1.5-2.5 kg/cm2}
pressure side
Pressure on high
1.37-1.57MPa{14-16 kg/cm2}
pressure side
s The figure shows the median of the gauge
pressure under the normal condition as an
example.
1. Gauge on high pressure side
2. Gauge on low pressure side
Air conditioner
52-9
(5)
(5)
TESTING AND ADJUSTING
PROCEDURE FOR CHARGING WITH REFRIGERANT
PROCEDURE FOR CHARGING WITH REFRIGERANT
k Take care that the refrigerant will not stick to
your hand.
k Put on protective goggles to prevent the refrigerant from entering your eyes.
s If the quantity of the refrigerant is insufficient,
add new refrigerant according to the following
procedure.
1. Evacuation
1) Stop the engine and install service tool kit N1.
s Close high-pressure valve (1) and lowpressure valve (2) of the gauge manifold
(in direction a).
s Connect red hose (3) to the high-pressure
piping and blue hose (4) to the low-pressure piping.
2) Connect green hose (5) to vacuum pump N2.
3) Open high-pressure valve (1) and low-pressure valve (2) gradually (in direction b).
s Do not operate the valves quickly.
4) Turn switch (6) of vacuum pump N2 ON and
evacuate the air conditioner circuit for 30
minutes.
5) Close high-pressure valve (1) and low-pressure valve (2) gradually (in direction a) and
turn switch (6) of the vacuum pump OFF.
2. Charging with refrigerant
1) Charging from high-pressure side
i)
Disconnect charging hose (Green) (5) of
the gauge manifold from vacuum pump
N2 and connect it to service can (7).
s When using 2 service cans, use service can valve T-joint (8).
ii) Tighten the handle of service can valve
(9) to pierce a hole in service can (7),
and then open service can valve (9) (in
direction b).
iii) Hold the valve of air purge valve (10) with
flat-head screwdriver (11) so that the air in
green hose (5) and gauge manifold will be
discharged by the refrigerant pressure.
s Continue the above work until the
refrigerant gas comes out with "a hiss".
iv) Stop the engine and open high-pressure
valve (1) and service can valve (9) to supply the refrigerant from service can (7) (in
direction b).
k Never drive the compressor.
k Do not drive the compressor while the air conditioner circuit is not charged with the refrigerant.
k Never open low-pressure valve (2).
(Set it in direction a.)
52-10
(5)
Air conditioner
TESTING AND ADJUSTING
2)
PROCEDURE FOR CHARGING WITH REFRIGERANT
v) Close high-pressure valve (1) and service can valve (9).
Charging from low-pressure side (Additional
charge)
i) Check that high-pressure valve (1) is
closed (in direction a).
ii) Open low-pressure valve (2) and service
can valve (9) under the condition in Table
1 and supply the refrigerant to a proper
level. (Each valve opens when it is set in
direction b.)
k Never open high-pressure valve (1).
k Never put service can (7) upside down.
s When measuring the refrigerant pres-
sure, close low-pressure valve (2)
and high-pressure valve (1) (in direction a).
s Note extremely that the proper refrigerant pressure depends on the air
conditioner suction temperature.
Table 1
Item
Condition
Door
Open full
Temperature control
Max.
Blower speed
Hi
External/Internal air
Internal
Engine speed
1,500rpm
Air conditioner switch
ON
Air conditioner refrigerant pressure standard
Air conditioner suc- High-pressure gauge prestion temperature (fC)
sure (MPa{kg/cm2})
15
1.03-1.32 {10.5-13.5}
20
1.17-1.47 {12.0-15.0}
25
1.32-1.62 {13.5-16.5}
30
1.47-1.77 {15.0-18.0}
35
1.62-1.91 {16.5-19.5}
iii) After finishing charging with the refrigerant, close low-pressure valve (2) and service can valve (9) and stop the engine.
iv) Check that the refrigerant is not leaking
with gas leak tester O.
Air conditioner
a.
b.
c.
d.
e.
Quantity of refrigerant is too much
Quantity of refrigerant is proper
Quantity of refrigerant is insufficient
Air conditioner suction temperature
High-pressure gauge pressure
52-11
(5)
TESTING AND ADJUSTING
PROCEDURE FOR CHARGING WITH REFRIGERANT
[Reference]
1. If the refrigerant circuit is empty, supply about
800 g of the refrigerant.
2. When the air conditioner suction temperature is in
the normal range of 30-35fC, the gauge pressure
becomes as shown in Table 2.
Table 2
<Gauge pressure indicated under normal condition>
Pressure on low
0.15-0.25MPa{1.5-2.5 kg/cm2}
pressure side
Pressure on high
1.37-1.57MPa{14-16 kg/cm2}
pressure side
s The figure shows the median of the gauge
pressure under the normal condition as an
example.
52-12
(5)
1. Pressure on low pressure side
2. Pressure on high pressure side
Air conditioner
TESTING AND ADJUSTING
PROCEDURE FOR REPLACING SERVICE CAN
PROCEDURE FOR REPLACING SERVICE CAN
kTake care that the refrigerant will not stick to
your hand.
k Put on protective goggles to prevent the refrigerant from entering your eyes.
1. Close high-pressure valve (1) and low-pressure
valve (2) (in direction a).
2. Raise needle (4) and disc (5) of service can
valve (3).
3. Install service can valve (3) to new service can
(6).
4. Tighten handle (7) of service can valve (3) to
pierce a hole in service can (6), and then open
handle (7) of service can valve (3) (in direction
b).
5. Hold the valve of air purge valve (8) with a flathead screwdriver so that the air in green hose
(10) and gauge manifold (11) will be discharged
by the refrigerant pressure.
s Continue the above work until the refrigerant
gas comes out with "a hiss".
Air conditioner
52-13
(5)
TESTING AND ADJUSTING
PROCEDURE FOR DISCHARGING REFRIGERANT
PROCEDURE FOR DISCHARGING REFRIGERANT
kTake care that the refrigerant will not stick to
your hand.
k Put on protective goggles to prevent the refrigerant from entering your eyes.
1)
2)
3)
Stop the engine and install service tool kit N1.
s Close the high-pressure valve and lowpressure valve of the gauge manifold.
s Connect blue hose (1) to the low-pressure
piping and red hose (2) to the high-pressure piping.
s If service tool kit N1 has not been
removed from the compressor after the
refrigerant pressure was measured, start
the work with 3) below.
Bleed air from service tool kit N1.
i) Open the high-pressure valve gradually.
When the refrigerant comes out of the
green charge hose with "a hiss", close the
high-pressure valve.
ii) Open the low-pressure valve gradually.
When the refrigerant comes out of the
green charge hose with "a hiss", close
the low-pressure valve.
Open the high-pressure valve (Hi) gradually
to release the refrigerant until the refrigerant
pressure lowers to the proper level when the
compressor is turned ON under the condition
in Table 1.
s Keep the low-pressure valve closed.
k Do not operate the high-pressure valve
quickly.
s When measuring the refrigerant pressure,
close the low-pressure valve and highpressure valve.
Table 1
Item
Condition
Door
Open full
Temperature control
Max.
Blower speed
Hi
External/Internal air
Internal
Engine speed
1,500rpm
Air conditioner switch
ON
52-14
(5)
Air conditioner
TESTING AND ADJUSTING
PROCEDURE FOR DISCHARGING REFRIGERANT
s Note that the proper refrigerant pressure
depends on the air conditioner suction
temperature.
Air conditioner refrigerant pressure standard
Air conditioner suc- High-pressure gauge prestion temperature (fC)
sure (MPa{kg/cm2})
15
1.03-1.32 {10.5-13.5}
20
1.17-1.47 {12.0-15.0}
25
1.32-1.62 {13.5-16.5}
30
1.47-1.77 {15.0-18.0}
35
1.62-1.91 {16.5-19.5}
[Reference]
When the air conditioner suction temperature is in
the normal range of 30-35fC, the gauge pressure
becomes as shown in Table 3.
a.
b.
c.
d.
e.
Quantity of refrigerant is too much
Quantity of refrigerant is proper
Quantity of refrigerant is insufficient
Air conditioner suction temperature
High-pressure gauge pressure
Table 3
<Gauge pressure indicated under normal condition>
Pressure on low
0.15-0.25MPa{1.5-2.5 kg/cm2}
pressure side
Pressure on high
1.37-1.57MPa{14-16 kg/cm2}
pressure side
s The figure shows the median of the gauge
pressure under the normal condition as an
example.
1. Pressure on low pressure side
2. Pressure on high pressure side
Air conditioner
52-15
(5)
TESTING AND ADJUSTING
CLEANING INTERNAL AND EXTERNAL AIR FILTERS
CLEANING INTERNAL AND EXTERNAL AIR FILTERS
1. Remove the upper 4 bolts of the luggage box
and bracket (1).
2. Remove the lower 2 bolts of the luggage box
and raise box (2) to remove.
3. Loosen wing bolt (3), move stopper (4), and pull
up internal air filter (5) to remove. Pull external
air filter (6) aside (to the left of the chassis) to
remove.
4. Clean filters (5) and (6) with compressed air. If
they are coated with oil or stained badly, wash
them in neutral detergent. After washing them in
water, dry them up.
s If the filters are clogged so badly that they can-
not be cleaned with air or water, replace them.
52-16
(5)
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING
TAKAHASHI WORKS
Electric circuit diagram of air conditioner................................................................................................. 52- 102
Wiring diagram related to air conditioner................................................................................................. 52- 104
Flowchart of troubleshooting ................................................................................................................... 52- 108
Air conditioner
52-101
(5)
TROUBLESHOOTING
ELECTRIC CIRCUIT DIAGRAM OF AIR CONDITIONER
ELECTRIC CIRCUIT DIAGRAM OF AIR CONDITIONER
52-102
(5)
Air conditioner
TROUBLESHOOTING
Air conditioner
ELECTRIC CIRCUIT DIAGRAM OF AIR CONDITIONER
52-103
(5)
TROUBLESHOOTING
WIRING DIAGRAM RELATED TO AIR CONDITIONER
WIRING DIAGRAM RELATED TO AIR CONDITIONER
*
The actual locations of the Hi, Mid, and Lo blower relays may be different from this drawing. Accordingly,
when carrying out troubleshooting, see the color symbols of the wiring harnesses in the electric circuit
diagram of the air conditioner and take care not to mistake the relays.
1. Servomotor for internal air and external air
2. Hi blower relay
3. Mid blower relay
4. Lo blower relay
Reference: The above figure is seen from front upper part of the chassis.
52-104
(5)
Air conditioner
TROUBLESHOOTING
WIRING DIAGRAM RELATED TO AIR CONDITIONER
1. Thermistor amplifier
2. Power supply relay
3. Hot water selector motor valve
4. Blower motor
5. Servomotor for blow mode
Reference: The above figure is seen from front upper part of the chassis.
Air conditioner
52-105
(5)
TROUBLESHOOTING
1.
2.
3.
4.
5.
6.
7.
Wiring harness on chassis side
Thermistor amplifier
Servomotor for internal air and external air
Hi blower relay
Mid blower relay
Lo blower relay
Blower resistor
52-106
(5)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
8.
9.
10.
11.
12.
13.
Blower motor
Air conditioner panel
Pressure cutout switch
Servomotor for blow mode
Servomotor for automatic damper
Power supply relay
Air conditioner
TROUBLESHOOTING
Air conditioner
WIRING DIAGRAM RELATED TO AIR CONDITIONER
52-107
(5)
M-26(a)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
TROUBLESHOOTING
M-26. Air conditioner does not operate
* Carry out the following troubleshooting when the battery and battery relay are normal.
* Before carrying out the following troubleshooting, check that fuses 3 and 5 are normal.
* Before carrying out the following troubleshooting, check that all the related connectors are properly inserted.
* Always connect any disconnected connectors before going on to the next step.
a) Air does not come out
YES
YES
2
YES Are internal and
external air filters
clogged?
3
When air conditioner
NO panel is replaced,
does air come out?
• Turn starting switch ON.
• Turn Hi, Mid, and Lo
switches ON in order.
• Turn air conditioner
switch ON.
1
Is resistance between
fuse 3-M26 (female) (2),
fuse 5-M26 (female) (5),
and M26 (female) (6)chassis ground normal?
• Max. 1Ω
• Turn starting switch
OFF.
• Disconnect M26
and fuses 3 and 5.
6
Is there continuity
YES between blower resistor (2)-(5), (6)-(1),
5
and (6)-(4)?
Is voltage between
YES power supply relay (4)
and chassis ground
4
normal?
Is resistance of each
air conditioner wiring
NO harness as shown in
Table 1?
• Turn starting switch
OFF.
• 24 V
• Turn starting switch
ON.
• Turn air conditioner
switch ON.
• Turn starting switch
OFF.
• Disconnect blower
resistor.
NO
NO
NO
52-108
(5)
Air conditioner
TROUBLESHOOTING
WIRING DIAGRAM RELATED TO AIR CONDITIONER
M-26(a)
Cause
(
Clogging of filters
See TESTING AND
ADJUSTING, Cleaning
internal and external air
filters of air conditioner
10 YES
Is there continuity
9 YES between blower resistor (1) and (2)?
Is voltage between
YES Lo blower relay (4)
and chassis ground
• Turn starting switch NO
8
normal?
OFF.
Is voltage between
• Disconnect blower
• 24 V
YES Mid blower relay (4)
motor.
• Turn starting switch ON.
and chassis ground
NO
•
Turn
air
conditioner
normal?
7
switch ON.
•
24 V
Is voltage between Hi
• Turn Lo switch ON.
YES blower relay (4) and
• Turn starting switch ON.
chassis ground nor• Turn air conditioner NO
mal?
switch ON.
• Turn Mid switch ON.
• 24 V
• Turn starting switch ON. NO
• Turn air conditioner
switch ON.
• Turn Hi switch ON.
NO
Remedy
)
Clean or
replace
Defective air conditioner
panel
Replace
Defective air conditioner
unit
Replace
Defective blower motor
Replace
Defective Lo blower relay
Replace
Defective Mid blower
relay
Replace
Defective Hi blower relay
Replace
Defective blower resistor
Replace
Replace
Defective power supply
relay
Air conditioner
Defect of defective contact in related wiring harness
Replace
Disconnection or defective contact in wiring harness between fuse 3-M26
(female) (2), fuse 5-M26
(female) (5), or M26
(female) (6)-chassis
ground
Repair
or
replace
52-109
(5)
TROUBLESHOOTING
M-26(a)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
Table 1
Terminals of both ends of wiring harness to be
measured
M26 (male) (5) - power supply relay (female) (1)
M26, power supply relay
M26 (male) (5) - Hi blower relay (female) (3)
M26, Hi blower relay
M26 (male) (5) - Mid blower relay (female) (3)
M26, Mid blower relay
M26 (male) (5) - Lo blower relay (female) (3)
M26, Lo blower relay
M26 (male) (5) - air conditioner panel (female) (11)
M26 (male) (6) - air conditioner panel (female) (1)
M26, air conditioner panel
M26 (male) (2) - blower resistor (female) (5)
M26, blower resistor
M26 (male) (6) - blower motor (female) (2)
M26, blower motor
Blower motor (female) (1) - blower resistor (female) (6)
Blower motor, blower resistor
Blower motor (female) (1) - Hi blower relay (female) (4)
Blower motor, Hi blower relay
Blower resistor (female) (2) - power supply relay (female) (2)
Blower resistor, power supply relay
Blower resistor (female) (2) - Hi blower relay (female) (2)
Blower resistor, Hi blower relay
Blower resistor (female) (1) - Mid blower relay (female) (4)
Blower resistor (female) (2) - Mid blower relay (female) (2)
Blower resistor (female) (2) - Lo blower relay (female) (2)
Blower resistor (female) (4) - Lo blower relay (female) (4)
Resistance
Connector to be disconnected
Max. 1Ω
Blower resistor, Mid blower relay
Blower resistor, Lo blower relay
Power supply relay (female) (3) - air conditioner panel (female) (6)
Power supply relay, air conditioner panel
Hi blower relay (female) (1) - air conditioner panel (female) (15)
Hi blower relay, air conditioner panel
Mid blower relay (female) (1) - air conditioner panel (female) (5)
Mid blower relay, air conditioner panel
Lo blower relay (female) (1) - air conditioner panel (female) (16)
Lo blower relay, air conditioner panel
52-110
(5)
Air conditioner
TROUBLESHOOTING
Air conditioner
WIRING DIAGRAM RELATED TO AIR CONDITIONER
52-111
(5)
M-26(b)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
TROUBLESHOOTING
b) Air comes out but it is not cold
Notes) 1. If troubleshooting item 5 cannot be judged, carry out troubleshooting item 6 or call the electric device
manufacturer.
2. If the result of troubleshooting item 6 is abnormal, carry out troubleshooting further, referring to Troubleshooting with gauge manifold.
YES
1
Is condenser clogged
or are fins bent down?
4
YES Is compressor belt
tension normal?
3
• Referring to operation manual, test compressor belt tension.
YES Does compressor
clutch click?
2
NO
Is voltage between
M34 and chassis
ground normal?
• Turn starting switch
ON.
• Turn air conditioner
switch ON.
• 24 V
• Turn starting switch
ON.
• Turn air conditioner
switch ON.
NO
NO
52-112
(5)
Go to A in page 52-114.
Air conditioner
M-26(b)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
TROUBLESHOOTING
Cause
Remedy
Clogging of condenser or
bending of fins
YES
6
YES
Only pressure on high pressure side is high
Only pressure on high pressure side is low
Only pressure on low pressure
side is high
NO
Only pressure on low pressure
side is low
5
YES
Is quantity of refrigerant in receiver tank
normal?
• Referring to section
of checking refrigerant,
check refrigerant level
visually.
-
Go to item 1 or call electric device manufacturer
Is refrigerant pressure normal?
• Referring to section
of checking refrigerant,
measure refrigerant
pressure.
Clean or
replace
Both pressures on high and low
sides are high
(
Both pressures on high and low
sides are low
Too much refrigerant
Entry of air, too much
refrigerant, or clogging of
condenser
Evacuate, discharge refrigerant, and
clean
Insufficient refrigerant, defective compressor, or defective
piping on low pressure side
(flattening or clogging)
Charge
with refrigerant or
replace
Defective air conditioner
unit or too much refrigerant
Replace or
discharge
refrigerant
Insufficient refrigerant, defective
air conditioner unit, or defective
piping on low pressure side
Charge
with refrigerant or
replace
)
Discharge
refrigerant
Insufficient refrigerant
See TESTING AND ADJUSTING,
Procedure for charging with refrigerant Insufficient refrigerant (See
TESTING AND ADJUSTING, Procedure for charging with refrigerant)
(
)
Charge
with refrigerant
(
Too much refrigerant
See TESTING AND ADJUSTING,
Procedure for discharging refrigerant
)
Discharge
refrigerant
Too much refrigerant
See TESTING AND ADJUSTING,
Procedure for discharging refrigerant
NO
Insufficient refrigerant
NO
Air conditioner
Insufficient refrigerant
See TESTING AND ADJUSTING,
Procedure for charging with refrigerant Insufficient refrigerant (See Procedure for charging with refrigerant)
Charge
with refrigerant
Defective adjustment of
compressor belt
(See operation manual)
Adjust
Defective compressor
Replace
52-113
(5)
M-26(b)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
TROUBLESHOOTING
YES
11
8
YES
When air conditioner
YES panel is replaced, is
air cooled?
10
• Turn starting switch
ON.
• Turn air conditioner
switch ON.
Is voltage between power
YES
supply relay (4) and
chassis ground normal?
9
7
Is resistance between
M26 (female) (3) and
M34 (female) normal?
A
NO
Is resistance of each air
conditioner wiring harness as shown in Table 1?
• 24 V
• Turn starting switch
ON.
• Turn air conditioner
switch ON.
Is resistance between
pressure cutout switch
(1) and (2) normal?
• Max. 1Ω
• Turn starting switch
ON.
• Turn air conditioner
switch ON.
• Disconnect pressure
cutout switch.
NO
• Turn starting switch
OFF.
• Max. 1Ω
• Turn starting switch
OFF.
• Disconnect M26 and
M34.
NO
NO
52-114
(5)
Air conditioner
M-26(b)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
TROUBLESHOOTING
Cause
12
When thermistor ampliYES fier is replaced, is air
cooled?
Defective air conditioner
panel
Replace
Defective thermistor amplifier
Replace
YES
Defective hot water selector motor valve
Replace
NO
Defective air conditioner
unit
Replace
Defective pressure cutout
switch
Replace
Defective power supply
relay
Replace
Defect or defective contact
in related wiring harness
Repair or
replace
Disconnection or defective
contact in wiring harness
between M26 (female) (3) M34 (female)
Repair or
replace
YES
13
When hot water selec• Turn starting switch
tor motor valve is
ON.
NO
replaced, is air cooled?
• Turn air conditioner
switch ON.
NO
Air conditioner
• Turn starting switch
ON.
• Turn air conditioner
switch ON.
Remedy
52-115
(5)
TROUBLESHOOTING
M-26(b)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
Table 1
Terminals of both ends of wiring harness to be
measured
Connector to be disconnected
M26 (male) (3) - Pressure cutout switch (female) (2)
M26, pressure cutout switch
M26 (male) (6) - Thermistor amplifier (female) (3)
M26, thermistor amplifier
Blower resistor (female) (2) - Power supply relay (female) (2)
Blower resistor, power supply relay
Power supply relay (female) (4) - Thermistor amplifier (female) (4)
Power supply relay, thermistor amplifier
Thermistor amplifier (female) (2) - Pressure cutout switch (female) (1)
Thermistor amplifier, pressure cutout switch
Hot water selector motor valve (female) (1) - Air conditioner panel (female) (18)
Hot water selector motor valve (female) (2) - Air conditioner panel (female) (8)
Hot water selector motor valve (female) (3) - Air conditioner panel (female) (19)
Hot water selector motor valve (female) (4) - Air conditioner panel (female) (20)
Resistance
Max. 1Ω
Hot water selector motor valve, air
conditioner panel
Hot water selector motor valve (female) (5) - Air conditioner panel (female) (10)
52-116
(5)
Air conditioner
M-26(b)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
TROUBLESHOOTING
Troubleshooting from gauge pressure
•
You can detect a defect in the refrigerating cycle by
checking the high and low pressure pointers of the
gauge manifold.
[Condition] * Warm up the engine, and then check
under the following condition.
Item
Condition
Door
Temperature control
Blower speed
EXTERNAL/INTERNAL air
Engine speed
Air conditioner suction temperature
and condenser suction temperature
Air conditioner switch
Open full
Max.
Hi
INTERNAL
1,500rpm
30fC-35fC
ON
1. Air conditioner is normal
<Gauge pressure indicated under normal condition>
Pressure on low
0.15-0.25MPa{1.5-2.5kg/cm2}
pressure side
Pressure on high
1.37-1.57MPa{14-16kg/cm2}
pressure side
2. Refrigerant is insufficient
<Indicated gauge pressure>
Pressure on low
pressure side
0.05-0.1MPa{0.5-1.0kg/cm2}
Pressure on high
pressure side
0.69-0.9MPa{7-10kg/cm2}
Check and remedy
point
Phenomenon
Cause
1.Both pressures on
high and low sides
are low
• Insufficiency
of refrigerant
• Check and repair
leaking part.
• Leakage of
refrigerant
• Add refrigerant.
2.Bubbles pass
through liquid eye
constantly
3.Blown air temperature
is not low
Air conditioner
• If pressure indicated
when gauge is connected is near 0, check
and repair leaking part,
and then evacuate circuit.
52-117
(5)
M-26(b)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
TROUBLESHOOTING
3. Circuit is charged with too much refrigerant or
condenser is not cooled sufficiently
<Indicated gauge pressure>
Pressure on low
0.25-0.35MPa{2.5-3.5kg/cm2}
pressure side
Pressure on high
1.96-2.45MPa{20-25kg/cm2}
pressure side
Phenomenon
Cause
1. Both pressures on
high and low sides
are high
• Too much
refrigerant
• Insufficient
cooling of
condenser
2.Even when engine
speed is low, no
bubbles are seen.
3.Air is not cooled
sufficiently
Check and remedy point
• Check quantity of
refrigerant.
• Adjust quantity of
refrigerant properly.
• Check and repair
condenser fins.
• Check CHASSIS
COOILNG SYSTEM,
Fan and radiator, etc.
4. Compressor does not compress normally
<Indicated gauge pressure>
Pressure on low
pressure side
0.4-0.6MPa{4.0-6.0kg/cm2}
Pressure on high
pressure side
0.69-0.98MPa{7-10kg/cm2}
Phenomenon
Cause
1.Pressure on low
pressure side is high
and that on high
pressure side is low
2.Just after air conditioner is turned OFF,
pressures on high
and low pressure
sides become the same
• Defective
compressor
Check and remedy point
• Replace compressor.
Reference: If compressor does not
compress normally
<Its body is not hot>
5. Expansion valve is opened too wide
<Indicated gauge pressure>
Pressure on low
pressure side
0.3-0.4MPa{3.0-4.0kg/cm2}
Pressure on high
1.96-2.45MPa{20-25kg/cm2}
pressure side
Phenomenon
Cause
1. Both pressures on
high and low sides
are high
• Defective
expansion valve
2. Piping on low
pressure side is
frosted (or coated
with dew)
52-118
(5)
Check and remedy point
• Check expansion
valve.
• Check installation
condition of heat
sensor tube.
Reference: This trouble occurs after expansion valve is replaced
in many cases.
Air conditioner
TROUBLESHOOTING
WIRING DIAGRAM RELATED TO AIR CONDITIONER
M-26
6. Air is in cycle
<Indicated gauge pressure>
Pressure on low
2
pressure side 0.25-0.35MPa{2.5-3.0kg/cm }
Pressure on high 1.96-2.45MPa{20-25kg/cm2}
pressure side
Phenomenon
1.Both pressures on
high and low sides
are high
2.Low-pressure piping is not cold
3.Bubbles pass
through liquid eye
Cause
• Entry of
air
Check and remedy point
• Replace refrigerant.
• After finishing work,
evacuate cycle
securely.
7. Refrigerant does not circulate (Cycle is clogged)
<Indicated gauge pressure>
Pressure on low
pressure side
Negative pressure
Pressure on high
pressure side
0.5-0.6MPa{5-6kg/cm2}
Phenomenon
Cause
1. If cycle is clogged
fully, negative pressure is indicated soon
on low pressure side
2. If cycle is clogged a
little, negative pressure is indicated
gradually on low pressure side
• Clogging
of air conditioner
cycle
Check and remedy point
• Check receiver,
expansion valve,
and compressor.
Reference: Temperatures at IN and
OUT sides of defective part are different.
• After finishing work,
evacuate cycle securely.
8. Water is in cycle
<Indicated gauge pressure>
• When normal
Pressure on low
0.15-0.25MPa{1.5-2.5kg/cm2}
pressure side
Pressure on high
2
pressure side 1.37-1.57MPa{14-16kg/cm }
• When abnormal
Pressure on low
pressure side
Negative pressure
Pressure on high
pressure side
0.69-0.98MPa{7-10kg/cm2}
Phenomenon
Cause
1. Air conditioner
operates normally
when it is started.
After a while, however, negative pressure is indicated on
low pressure side.
• Freezing
of water
around
expansion
valve
Air conditioner
Check and remedy point
• Check expansion
valve, etc.
• Replace receiver
drier
• After finishing work,
evacuate cycle
securely.
52-119
(5)
M-26(c)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
TROUBLESHOOTING
c) Internal air and external air cannot be selected
Cause
Remedy
YES
Defective air conditioner
panel
Replace
Defective servomotor for
internal air and external air
Replace
Defective linkage or defective air conditioner unit
Adjust or
replace
Defect or defective contact
in related wiring harness
Repair or
replace
1
When air conditioner
panel is replaced, can
internal air and external air be selected?
3
When servomotor for interYES nal air and external air is
2
• Turn starting switch
replaced, can internal air and
Is resistance of each
ON.
external air be selected?
air conditioner wiring
• Turn air conditioner
switch ON.
harness as shown in
• Change EXTERNAL/ NO Table 1?
INTERNAL air changeover switch between
EXTERNAL and
INTERNAL positions.
YES
NO
• Turn starting switch
OFF.
NO
Table 1
Terminals of both ends of wiring harness to be
measured
Servomotor for internal air and external air (female) (1) - Air conditioner panel (female) (17)
Servomotor for internal air and external air (female) (2) - Air conditioner panel (female) (13)
Servomotor for internal air and external air (female) (3) - Air conditioner panel (female) (3)
52-120
(5)
Connector to be disconnected
Resistance
Servomotor for internal air and
external air, air conditioner panel
Max. 1Ω
Air conditioner
TROUBLESHOOTING
WIRING DIAGRAM RELATED TO AIR CONDITIONER
M-26(d,e)
d) Air outlet cannot be selected
Cause
Remedy
YES
Defective air conditioner
panel
Replace
Defective servomotor for
blow mode
Replace
Defective linkage or defective air conditioner unit
Adjust or
replace
Defect or defective contact
in related wiring harness
Repair or
replace
1
3
When air conditioner
panel is replaced, can
air outlet be selected?
When servomotor
YES for blow mode is
replaced, can air
• Turn starting switch
outlet be selected?
2
ON.
Is resistance of each
• Turn starting switch ON.
• Turn air conditioner
air conditioner wiring
• Turn air conditioner
switch ON.
switch ON.
• Set air outlet selec- NO harness as shown in
• Set air outlet selecTable 1?
tor switch to FACE
and FOOT.
YES
NO
tor switch to FACE
and FOOT.
• Turn starting switch
OFF.
NO
Table 1
Terminals of both ends of wiring harness to be
measured
Servomotor for blow mode (female) (1) - Air conditioner panel (female) (7)
Servomotor for blow mode (female) (2) - Air conditioner panel (female) (4)
Servomotor for blow mode (female) (3) - Air conditioner panel (female) (14)
Connector to be disconnected
Resistance
Servomotor for internal air and
external air, air conditioner panel
Max. 1Ω
e) Air flow rate does not change
1
YES
Is resistance between
Hi and Mid blower
relay (2) and (4) normal?
• Min. 1ΜΩ
• Turn starting switch
OFF.
• Disconnect related
blower relay.
Air conditioner
NO
Cause
Remedy
Defective air conditioner
panel
Replace
Melting of contacts between
related blower relay (2) - (4)
Replace
52-121
(5)
TROUBLESHOOTING
52-122
(5)
WIRING DIAGRAM RELATED TO AIR CONDITIONER
Air conditioner
STRUCTURE AND FUNCTION
STRUCTURE AND FUNCTION
SANDEN
Basic system of air, heater, and cooler...................................................................................................... 61- 3
Control panel ............................................................................................................................................. 61- 7
Compressor, condenser, and receiver drier............................................................................................... 61- 9
Air conditioner
61-1
(5)
STRUCTURE AND FUNCTION
61-2
(5)
SANDEN
Air conditioner
STRUCTURE AND FUNCTION
BASIC SYSTEM OF AIR, HEATER, AND COOLER
1. BASIC SYSTEM OF AIR, HEATER, AND COOLER
1.
2.
3.
4.
5.
6.
7.
Air conditioner unit
Control panel
Condenser
Air conditioner piping
Compressor
Receiver drier
Engine coolant piping
a. To engine
b. From engine
Outline
This system is an air conditioner unit which consists
of a evaporator, heater core, blower, etc. and blows
out cold air and hot air.
• In heating mode
Air in the cab is sucked in through the suction opening and heat-exchanged (heated) in the heater core
of the air conditioner unit, and then blown out
through the duct and grille. The heat source of the
heater core is the engine coolant.
The blow temperature is adjusted with the temperature adjustment switch on the control panel. If the
temperature adjustment switch is operated, the
water valve of the air conditioner unit opens or
closes to adjust the engine coolant flow rate, or
adjust the temperature.
• In cooling mode
Air in the cab is sucked in through the suction opening and heat-exchanged (dehumidified and cooled)
in the evaporator of the air conditioner unit, and then
blown out through the duct and grille.
Air conditioner
61-3
(5)
STRUCTURE AND FUNCTION
BASIC SYSTEM OF AIR, HEATER, AND COOLER
1-1. Detail of air conditioner unit
61-4
(5)
Air conditioner
STRUCTURE AND FUNCTION
BASIC SYSTEM OF AIR, HEATER, AND COOLER
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
Unit fixing frame
Packing
Packing
Bell mouth
Blower case
Blower and blower motor assembly
Motor fixing plate
Packing
Unit panel
Bracket
Packing
Packing
Wiring harness assembly
Band
Packing
Spacer
Intake damper
Spring
Lever knob
Sensor holder
Thermistor
Evaporator
Expansion valve
Outlet and inlet pipe assembly
(Equipped with dual pressure switch)
Packing
Resistor
Packing
Packing
Packing
External air intake duct
EXTERNAL/INTERNAL air changeover lever
Heater core and evaporator mounting bracket
Heater core
Hose clamp
Heater hose
Hose packing
Bracket
Bracket
Water valve assembly
Heat insulation material
Air conditioner
Packing
Unit bottom plate
Drain fitting
Packing
Packing
Grommet
Unit fixing frame
Packing
Grommet
Unit case
Packing
Packing
61-5
(5)
STRUCTURE AND FUNCTION
BASIC SYSTEM OF AIR, HEATER, AND COOLER
1-2. Component parts in air conditioner unit (Parts related to control)
Resistor
The resistor outputs signals according to the position of the blower switch to change the fan motor
speed of the blower.
Thermistor
The thermistor senses the blow-out temperature of
the evaporator, outputs signals, and turns the compressor ON and OFF to prevent the evaporator from
freezing. It is installed to the outlet side of the evaporator.
Dual pressure switch
When the refrigerant pressure on the high pressure
side becomes abnormal, the dual pressure switch
outputs a signal to turn the compressor OFF to protect the refrigerating cycle. This switch is installed to
the high-pressure piping side of the outlet and inlet
pipe assembly.
This switch is turned OFF when the refrigerant pressure is below 0.1MPa {2.0 kg/cm2} or above 3.1MPa
{32 kg/cm2}.
61-6
(5)
Air conditioner
STRUCTURE AND FUNCTION
CONTROL PANEL
2. CONTROL PANEL
1.
2.
3.
4.
5.
6.
7.
8.
Band
Air conditioner relay
Knob
Air conditioner switch
Nameplate
Case
Air flow selector switch (Blower switch)
Temperature adjustment switch (Thermal control
knob)
9. Bracket
10. Control amplifier
Outline
The control panel compares and calculates the input
signals of various switches and sensors with the
microcomputer of the control amplifier in it and controls the water valve actuator, blower motor, and
compressor.
2-1. Operation unit of panel
1. Temperature adjustment switch
2. Air flow selector switch
3. Air conditioner switch
Air conditioner
61-7
(5)
STRUCTURE AND FUNCTION
CONTROL PANEL
2-2. Component parts in control box
Temperature adjustment switch (Thermal control knob)
If the knob of the temperature adjustment switch is
turned, the ON-OFF operation point of the air conditioner compressor and the opening ratio of the water
valve change. As a result, the temperature of the air
from the evaporator and heater core changes. Consequently, the temperature of the air blown out from
the air conditioner unit changes.
Air conditioner switch
If this switch is pressed while the air flow selector
switch is turned ON, the compressor operates
according to the position of the temperature adjustment switch and blow-out temperature of the evaporator.
Air flow selector switch (Blower switch)
If the knob of the air flow selector switch is turned, the
air flow from the air conditioner unit is stopped or set to
3 levels.
Compressor relay
The compressor relay turns the compressor ON and
OFF according to the setting of the control amplifier
and electronic thermal control system.
61-8
(5)
Air conditioner
STRUCTURE AND FUNCTION
COMPRESSOR, CONDENSER, AND RECEIVER DRIER
3. COMPRESSOR, CONDENSER, AND RECEIVER DRIER
1.
2.
3.
4.
5.
6.
7.
8.
Air conditioner piping (Low pressure)
Air conditioner piping (High pressure)
Condenser
Air conditioner piping (High pressure)
Bracket
Receiver drier
Air conditioner piping (High pressure)
Compressor
Outline
The refrigerant gas returned from the evaporator is
compressed by the compressor and its temperature
and pressure rise. Then, it is sent to the condenser
and cooled and liquefied there. Dirt and water in the
refrigerant liquid are removed by the receiver drier.
Then, the refrigerant liquid is sent through the
expansion valve to the evaporator and evaporated
there.
a. From air conditioner unit (evaporator)
b. To air conditioner unit (evaporator)
Air conditioner
61-9
(5)
STRUCTURE AND FUNCTION
61-10
(5)
COMPRESSOR, CONDENSER, AND RECEIVER DRIER
Air conditioner
TROUBLESHOOTING
TESTING AND ADJUSTING
SANDEN
Troubleshooting ........................................................................................................................................ 62-101
Air conditioner
62-1
(5)
TROUBLESHOOTING
62-2
(5)
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING
SANDEN
Information in troubleshooting table ......................................................................................................... 62-102
Air conditioner is defective........................................................................................................................ 62-103
Related electric circuit diagram ................................................................................................................ 62-107
Air conditioner
62-101
(5)
TROUBLESHOOTING
INFORMATION IN TROUBLESHOOTING TABLE
INFORMATION IN TROUBLESHOOTING TABLE
s The following information is summarized in the troubleshooting table and the related electrical circuit dia-
gram. Before carrying out troubleshooting, understand that information fully.
User code
Error code
Failure code
Panel display
Panel display
Panel display
Trouble
Trouble name displayed in trouble record
Contents of trouble Condition at the time when the monitor panel or controller detects the trouble
Action of monitor The action taken by the monitor panel or controller to protect the system or devices when the
panel or controller monitor panel or controller detects the trouble
Problem that The problem that appears on the machine as a result of the action taken by the monitor panel
appears on or controller (shown above)
machine
Related information Information related to the detected trouble or troubleshooting
Cause
Standard value in normal state/Remarks on troubleshooting
<Contents of description>
• Standard value in normal state to judge possible causes
• Remarks on judgment
1
2
Possible
causes and
standard value 3
in normal state
(
Possible causes of trouble
Given numbers are reference numbers, which do
not indicate priority
)
<Troubles in harness>
• Disconnection
Connector is connected imperfectly or harness is broken.
• Grounding fault
Harness which is not connected to chassis ground circuit
is in contact with chassis ground circuit.
• Short circuit with power source
Harness which is not connected to power source (24-V)
circuit is in contact with power source (24-V) circuit.
4
5
62-102
(5)
Air conditioner
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
AIR CONDITIONER IS DEFECTIVE
a) Air conditioner does not operate
User code
Error code
Failure code
-
-
-
Trouble
Air conditioner is defective
a) Air conditioner does not operate
Contents of trouble • The air conditioner does not operate.
Action of monitor panel or controller
Problem that appears on
machine
• Check that the fuse is not broken and the wiring harness between connectors is free of disconnection in advance.
Related information • If the air conditioner switch is turned ON but no air comes out when the air flow selector
switch (blower switch) is turned ON (set in position 1, 2, or 3), carry out troubleshooting for
"b) Air does not come out or air flow does not change" in advance.
Cause
Standard value in normal state/Remarks on troubleshooting
s Prepare with starting switch OFF, then carry out trouble-
shooting without turning starting switch ON.
1
Defective air conditioner switch
Air conditioner switch connector
C-D
Possible
causes and
standard value
in normal state
2
3
Disconnection in wiring harness
(Disconnection in wiring harness or defective contact in
connector)
Short circuit with
chassis ground in
wiring harness
(Contact with ground
circuit)
Switch position
Resistance
ON
Max. 1Ω
OFF
Min. 1MΩ
s Prepare with starting switch OFF, then carry out trouble-
shooting without turning starting switch ON.
Referring to the circuit diagram, check
continuity between connectors.
Resistance
Max. 1Ω
s Prepare with starting switch OFF, then carry out trouble-
shooting without turning starting switch ON.
Referring to the circuit diagram, check
insulation between each connector and
ground (excluding ground circuit).
ResisMin. 1MΩ
tance
s Prepare with starting switch OFF, then turn starting switch
ON and carry out troubleshooting.
4
Air conditioner
Defective control
amplifier
Replace with
normal control
amplifier.
Condition
becomes normal
Condition does not
become normal
Control amplifier is defective
Control amplifier is normal
62-103
(5)
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
b) Air does not come out or air flow does not change
User code
Error code
Failure code
Air conditioner is defective
Trouble b) Air does not come out
Contents of trouble • Air does not come out or air flow does not change
Action of monitor panel or controller
Problem that appears on
machine
Related information • Check that the fuse is not broken and the wiring harness between connectors is free of disconnection in advance.
Cause
Possible
causes and
standard value
in normal state
62-104
(5)
1
Defective air flow
selector switch
(blower switch)
2
Defective resistor
3
Defective blower
motor
4
Disconnection in wiring harness
(Disconnection in wiring
harness or defective
contact in connector)
5
Short circuit with chassis
ground in wiring harness
(Contact with ground circuit)
6
Defective control
amplifier
Standard value in normal state/Remarks on troubleshooting
s Prepare with starting switch OFF, then carry out trouble-
shooting without turning starting switch ON.
Knob position
Resistance
Air flow selector switch terminal
0
Min. 1MΩ
Between all terminals
Max. 1Ω
Between B - L/R, B - L/W, and L/R - L/W
1
Min. 1MΩ
Between terminals other than above
Max. 1Ω
Between B - L/R, B - L/Y, and L/R - L/Y
2
Min. 1MΩ
Between terminals other than above
Max. 1Ω
Between B - L/R, B - L/B, and L/R - L/B
3
Min. 1MΩ
Between terminals other than above
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Resistor terminals
Resistance
Between L and M1
Approx. 1.8Ω
Between M1 and M2
Approx. 0.7Ω
Between M2 and M0
Approx. 0.3Ω
s Prepare with starting switch OFF, then turn starting switch
ON and carry out troubleshooting.
Blower motor is
Condition
Replace with
defective
becomes normal
normal blower
Blower motor is
Condition does not
motor
normal
become normal
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Referring to the circuit diagram, check
ResisMax. 1Ω
continuity between connectors.
tance
s Prepare with starting switch OFF, then carry out trouble-
shooting without turning starting switch ON.
Referring to the circuit diagram, check
Resisinsulation between each connector and
tance Min. 1MΩ
ground (excluding ground circuit).
s Prepare with starting switch OFF, then turn starting switch
ON and carry out troubleshooting.
Condition
Control ampliReplace with
becomes normal
fier is defective
normal control
Condition does not
Control ampliamplifier
become normal
fier is normal
Air conditioner
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
c) Blow-out temperature cannot be adjusted
User code
Error code
Failure code
-
-
-
Trouble
Air conditioner is defective
c) Blow-out temperature cannot be adjusted
Contents of trouble • The blow-out temperature cannot be adjusted.
Action of monitor panel or controller
Problem that appears on
machine
Check that hot water is supplied to the inlet side of the water valve in advance.
Related information •• Check
that the fuse is not broken and the wiring harness between connectors is free of disconnection in advance.
Cause
1
Defective temperature adjustment
switch
2
Defective water valve
assembly
3
Disconnection in wiring harness
(Disconnection in wiring
harness or defective
contact in connector)
4
Short circuit with chassis ground in wiring
harness
(Contact with ground circuit)
5
Defective control
amplifier
Possible
causes and
standard value
in normal state
Air conditioner
Standard value in normal state/Remarks on troubleshooting
s Prepare with starting switch OFF, then turn starting switch ON and turn
blower switch ON (Set it in 1, 2, or 3) and carry out troubleshooting.
Voltage
Temperature adjustment switch connector (2)
Changes
between
G/B-G/W
0 and approx. 5 V
Changes between
G/B-Y/B
0 and approx. 5 V
G/B-Y/W
Approx. 5V
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Temperature adjustment switch
Knob position
Resistance
connector (2) (Switch side)
COOL-MAX m Middle position Approx. 2.3kΩm Max. 1Ω
Y/W-Y/B
Max. 1Ω
Middle position m HOT-MAX
COOL-MAX m Middle position Approx. 2.3kΩ
Y/W-G/W
Middle position m HOT-MAX Approx. 2.3kΩm Max. 1Ω
s Prepare with starting switch OFF, then turn starting switch ON and turn
blower switch ON (Set it in 1, 2, or 3) and carry out troubleshooting.
Operation Rod operates according to operation of temperature adjustment switch
s Prepare with starting switch OFF, then turn starting switch
ON and carry out troubleshooting.
Replace with normal Condition becomes normal Water valve assembly is defective
water valve assembly Condition does not become normal Water valve assembly is normal
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Referring to the circuit diagram, check continu- Resisity between connectors.
tance Max. 1Ω
s Prepare with starting switch OFF, then carry out trouble-
shooting without turning starting switch ON.
Referring to the circuit diagram, check insulation between Resis- Min. 1MΩ
tance
each connector and ground (excluding ground circuit).
s Prepare with starting switch OFF, then turn starting switch
ON and carry out troubleshooting.
Condition becomes normal Control amplifier is defective
Replace with normal
control amplifier
Condition does not become normal Control amplifier is normal
62-105
(5)
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
d) Air is not cooled or temperature cannot be adjusted (Electrical system)
User code
Error code
-
Failure code
-
-
Trouble
Air conditioner is defective
d) Air is not cooled or temperature cannot be
adjusted (Electrical system)
Contents of trouble • Air is not cooled or temperature cannot be adjusted (Electrical system).
Action of monitor panel or controller
Problem that appears on
machine
Related information
• When the ambient temperature is below 2fC, this phenomenon does not indicate a trouble.
• Check that the fuse is not broken and the wiring harness between connectors is free of disconnection in advance.
Cause
1
Defective compressor clutch
2
Defective dual pressure switch
3
Defective air conditioner switch
4
Defective compressor relay
5
Defective thermistor
6
Disconnection in wiring harness
(Disconnection in wiring harness
or defective contact in connector)
7
Short circuit with chassis ground in wiring
harness
(Contact with ground circuit)
8
Defective control
amplifier
Possible
causes and
standard value
in normal state
62-106
(5)
Standard value in normal state/Remarks on troubleshooting
s Prepare with starting switch OFF, then turn starting switch
ON and carry out troubleshooting.
Between (12) and chassis ground
Voltage 10-15V
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Resis- Max. 1Ω
Dual pressure switch connector
tance
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Air conditioner switch
Switch position
Resistance
connector
ON
Max. 1Ω
C-D
OFF
Min. 1MΩ
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Compressor relay connector
(1)-(2)
Resistance
Approx. 320Ω
Source voltage
Resistance
between (1) and (2)
Applied
Max. 1Ω
(3)-(4)
Not applied
Min. 1MΩ
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Thermistor connector Test temperature
Resistance
0fC
Approx. 7.2kΩ
B/W-B/R
25fC
Approx. 2.2kΩ
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Referring to the circuit diagram, check
ResisMax. 1Ω
continuity between connectors.
tance
s Prepare with starting switch OFF, then carry out troubleshooting without turning starting switch ON.
Referring to the circuit diagram, check
Resisinsulation between each connector and
Min. 1MΩ
tance
ground (excluding ground circuit).
s Prepare with starting switch OFF, then turn starting switch
ON and carry out troubleshooting.
Condition
Control amplifier is defective
Replace with
becomes normal
normal control
Condition does not Control amplifier is normal
amplifier
become normal
Compressor relay connector
Air conditioner
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
Related electric circuit diagram
Air conditioner
62-107
(5)
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
e) Air is not cooled sufficiently (Mechanical system)
User code
Error code
-
Failure code
-
-
Trouble
Air conditioner is defective
e) Air is not cooled sufficiently (Mechanical system)
Contents of trouble • Air is not cooled sufficiently because of a trouble in the mechanical system.
Action of monitor panel or controller
Problem that appears on
machine
Related information Cause
1
Refrigerant leakage
through piping joint or part
• Check, then repair or replace if necessary.
2
Natural leakage
through hoses (Refrigerant has not been
added for long period)
• Check quantity of refrigerant, then add new refrigerant if
necessary.
3
Insufficient refrigerant
• Add refrigerant to proper level.
4
Defective expansion
valve
• Check, then repair or replace if necessary.
s Check expansion valve for opening too wide and check
heat sensor tube for defective contact.
5
Clogging of low-pressure circuit or evaporator
• Check for clogging, then clean or replace.
6
Clogging of evaporator fins
• Check for clogging, then clean evaporator if necessary.
Clogging of filter
• Check, then clean or replace.
Defective installation
of thermistor
• Check, then repair or replace if necessary.
9
Air leakage through
joint of air conditioner
unit and duct
• Check, then repair or replace leaking part.
10
Insufficient set air
flow rate
• Increase set air flow rate.
11
Too much refrigerant
• Check quantity of refrigerant, then discharge refrigerant to
proper level if necessary.
12
Entry of air
• Evacuate cycle, then charge it with refrigerant to proper
level and replace receiver drier.
13
Clogging of condenser fins
• Check for clogging, then clean fins if necessary.
14
Defective compression by compressor
• Check, then repair or replace.
15
Water in refrigerant circuit
• Evacuate cycle, then charge it with refrigerant to proper
level and replace receiver drier.
Possible
7
causes and
standard value
in normal state 8
62-108
(5)
Standard value in normal state/Remarks on troubleshooting
Air conditioner
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
f) Air is not heated sufficiently (Hot water circuit is defective)
User code
Error code
Failure code
Air conditioner is defective
Trouble f) Air is not heated sufficiently (Hot water circuit is defective)
Contents of trouble Air is not heated sufficiently (Hot water circuit is defective).
Action of monitor panel or controller
Problem that appears on
machine
• Check that water is not leaking through the hot water circuit.
Related information • Check that air if blown from air outlet.
Cause
1
Clogging of heater
core fins
2
Air leakage through
air conditioner unit
Possible
causes and
standard value 3
in normal state
Defective water valve
(clogging, defective
valve)
4
Clogging of heater
core
5
Clogging before hot
water inlet of heater
core
Standard value in normal state/Remarks on troubleshooting
• Check heater core fins for clogging. If clogged, clean them.
s If this is the cause, the temperature of the heater core hot water inlet
is high and that of the heater core hot water outlet is also high.
• Check the air conditioner unit for air leakage, then repair
or replace if necessary.
s If this is the cause, the temperature of the heater core hot water inlet
is high and that of the heater core hot water outlet is also high.
• Check the water valve for clogging of defect in the valve,
then clean or replace it.
s If this is the cause, the temperature of the heater core hot water
inlet is high but that of the heater core hot water outlet is low.
• Check inside of the heater core for clogging, then repair or
replace it if necessary.
s If this is the cause, the temperature of the heater core hot water
inlet is high but that of the heater core hot water outlet is low.
• Check the piping before the heater core for clogging, then
repair or replace if necessary.
s If this is the cause, the temperature of the heater core hot water inlet is low.
g) Abnormal sound comes out
User code
Contents of trouble
Action of monitor
panel or controller
Problem that
appears on
machine
Related information
Error code
Failure code
• Abnormal sound comes out.
-
Air conditioner is defective
g) Abnormal sound comes out
-
1
2
Possible
3
causes and
standard value
in normal state 4
5
6
7
Air conditioner
Trouble
Cause
Defective installation of case
mounting bolts (screws)
Interference of fan case,
etc. or breakage of fan
Foreign matter in blower motor
or defective blower motor
Defective expansion
valve
Loosened or worn
compressor belt
Too much or insufficient refrigerant
Defective compressor
Standard value in normal state/Remarks on troubleshooting
• Check, then repair if necessary.
• Check, then repair or replace if necessary.
• Check, then remove foreign matter and repair or replace if
necessary.
• Check, then replace if abnormal sound (blowing sound or
hiss of refrigerant) is detected.
• Check, then repair or replace if looseness or wear is
detected.
• Check the quantity of the refrigerant. If it is too much or
insufficient, adjust it properly.
• Check, then repair or replace if necessary.
62-109
(5)
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
h) Water leaks
User code
Error code
Failure code
-
-
-
Trouble
Air conditioner is defective
h) Water leaks
Contents of trouble • Water leaks.
Action of monitor panel or controller
Problem that appears on
machine
Related information Cause
1
Clogging of water
drain hole in air conditioner unit
• Check, then repair if necessary.
2
Clogging, bending,
defective installation,
or hole of drain hose
of air conditioner unit
• Check, then repair or replace if necessary.
Cracking of air conditioner unit case
• Check, then repair or replace if any crack is detected.
4
Defective mounting
bolts (screws) of air
conditioner unit case
• Check, then repair or replace if necessary.
5
Development pipe joints
of hot water circuit
• Check, then repair or replace if necessary.
6
Defective heater core
• Check, then repair or replace if necessary.
7
Defective water valve
• Check, then repair or replace if necessary.
Possible
causes and
standard value 3
in normal state
62-110
(5)
(5)
Standard value in normal state/Remarks on troubleshooting
Air conditioner
TROUBLESHOOTING
AIR CONDITIONER IS DEFECTIVE
i) Internal air and external air cannot be selected
User code
Error code
-
Failure code
-
-
Trouble
Air conditioner is defective
i) Internal air and external air cannot be
selected
Contents of trouble • Internal air and external air cannot be selected.
Action of monitor panel or controller
Problem that appears on
machine
Related information Cause
1
Possible
causes and
standard value
in normal state 2
3
Air conditioner
Standard value in normal state/Remarks on troubleshooting
Malfunction of external/internal air
changeover lever
• Check, then clean and repair or replace if necessary.
Malfunction of intake
damper
• Check, then clean and repair or replace if necessary.
Clogging of external
air intake duct of unit
• Check, then clean if necessary.
62-111
(5)
(5)
TROUBLESHOOTING
62-112
(5)
AIR CONDITIONER IS DEFECTIVE
Air conditioner
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY AND ASSEMBLY
SANDEN
Disassembly, assembly of air conditioner unit .......................................................................................... 63-
2
Disassembly, assembly of control panel....................................................................................................63- 11
Air conditioner
63-1
(5)
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
63-2
(5)
Air conditioner
DISASSEMBLY AND ASSEMBLY
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
Unit fixing frame
Packing
Packing
Bell mouth
Blower case
Blower and blower motor assembly
Motor fixing plate
Packing
Unit panel
Bracket
Packing
Packing
Wiring harness assembly
Band
Packing
Spacer
Intake damper
Spring
Lever knob
Sensor holder
Thermistor
Evaporator
Expansion valve
Outlet and inlet pipe assembly
(Equipped with dual pressure switch)
Packing
Resistor
Packing
Packing
Packing
External air intake duct
EXTERNAL/INTERNAL air changeover lever
Heater core and evaporator mounting bracket
Heater core
Hose clamp
Heater hose
Hose packing
Bracket
Bracket
Water valve assembly
Heat insulation material
Air conditioner
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
Packing
Unit bottom plate
Drain fitting
Packing
Packing
Grommet
Unit fixing frame
Packing
Grommet
Unit case
Packing
Packing
63-3
(5)
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
DISASSEMBLY
1. Remove external/internal air changeover lever
(31).
2. Remove unit fixing frame (1).
3. Remove bracket (10) and unit panel (9) from unit
case (50).
4. Remove wiring harness assembly (13).
5. Remove blower case (5) from unit case (50).
6. Remove bell mouth (4) from blower case (5).
7. Remove motor fixing plate (7) from blower case
(5).
8. Remove clip (53) and fan (54).
s Remove fan (54) stamped with R.
9. Pull blower and blower motor assembly (6) out
of blower case (5).
63-4
(5)
Air conditioner
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
10. Remove unit bottom plate (42) and packing (41)
from unit case (50).
11. Remove evaporator, expansion valve, and outlet/inlet pipe assembly (55).
s Take care not to damage wiring harness (57).
12. Disassemble the evaporator, expansion valve,
and outlet/inlet pipe assembly into evaporator
(22), expansion valve (23), and outlet/inlet pipe
assembly (24).
13. Remove 2 sensor holders (20) from evaporator
(22).
14. Remove thermistor (21) from sensor holder (20).
Air conditioner
63-5
(5)
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
15. Remove grommets (49).
16. Remove heater hose (35).
17. Remove brackets (37) and (38) and heater core
(33).
18. Remove water valve assembly (39) from unit
case (50).
63-6
(5)
Air conditioner
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
ASSEMBLY
1. Install water valve assembly (39) to unit case
(50).
2. Install heater core (33) and secure it with brackets (37) and (38).
3. Install heater hose (35).
s Install hose clamp (34) securely.
s Install heater hose (35) so that part "a" will be
in parallel.
4. Install grommets (49) to outlet and inlet of the
heater pipe.
5. Install thermistor (21) to sensor holder (20).
s Install the thermistor so that only sensor unit (56)
will be projected to the side of sensor holder (20).
6. Install sensor holder (20) to evaporator (22).
s Install the sensor holder so that sensor unit (56) of the
thermistor will be set as shown in the following figure.
Distance a: 130 mm from end of fine
Distance b: 210 mm from end of evaporator (19th fin)
Air conditioner
63-7
(5)
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
7. Install expansion valve (23) and outlet/inlet pipe
assembly (24) to evaporator (22).
8. Install evaporator, expansion valve, and outlet/
inlet pipe assembly (55).
s Put wiring harness (57) on water valve assembly (39) side.
9. Install packing (41) and unit bottom plate (42) to
unit case (50).
10. Install blower and blower motor assembly (6) to
blower case (5).
11. Install fan (54) to the motor shaft and secure it
with clip (53).
s Check that there is the a stamp of R on fan
(54).
12. Install motor fixing plate (7) to blower case (5) and
secure blower and blower motor assembly (6).
s Tighten 2 bolts a first.
63-8
(5)
Air conditioner
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
s Install blower and blower motor assembly (6)
so that wiring harness (58) and motor cooling
hole (59) will be set as shown in the following
figure.
s Install the blower and blower motor assembly
so that clearance a between fan (55) and
blower case (5) will be as follows.
Clearance a: 4 v0.5 mm
13. Install bell mouth (4) to blower case (5).
14. Install blower case (5).
s Set the blower case diagonally as shown in the
following figure, and then push in the part
marked with the arrow to install.
s Pass wiring harness (58) through part a in
advance.
Air conditioner
63-9
(5)
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT
15. Connect wiring harness assembly (13) to each
part in the unit.
16. Install unit panel (9) to unit case (50).
s Fix the grommet of wiring harness assembly
(13) to the cut of part a.
17. Install bracket (10).
18. Install unit fixing frame (1).
19. Install external/internal air changeover lever
(31).
63-10
(5)
(5)
Air conditioner
DISASSEMBLY AND ASSEMBLY
DISASSEMBLY, ASSEMBLY OF CONTROL PANEL
DISASSEMBLY, ASSEMBLY OF CONTROL PANEL
1.
2.
3.
4.
5.
Band
Air conditioner relay
Knob
Air conditioner switch
Nameplate
6.
7.
8.
9.
10.
Case
Air flow selector switch (Blower switch)
Temperature adjustment switch (Thermal control knob)
Bracket
Control amplifier
DISASSEMBLY
ASSEMBLY
1. Remove knob (3).
2. Remove air flow selector switch (blower switch)
(7) and temperature adjustment switch (thermal
control knob) (8).
3. Hold the stopper claws and remove air conditioner switch (4).
4. Remove bracket (9) and control amplifier (10)
together.
s Do not give an impact to these parts.
5. Remove air conditioner relay.
1. Install air conditioner relay (2).
2. Install bracket (9) and control amplifier (10)
together.
3. Push air conditioner switch (4) straight into case
(6) to install.
4. Install air flow selector switch (blower switch) (7)
and temperature adjustment switch (thermal
control knob) (8).
5. Install knob (3).
s Check that you can operate the control panel
smoothly.
Air conditioner
63-11
(5)
(5)
STRUCTURE AND FUNCTION
STRUCTURE AND FUNCTION
ZEXEL VALEO (NEW REFRIGERANT (R134a) TYPE)
Comparison of applicable models and air conditioner units .................................................................... 71-
2
Configuration and functions of refrigerating cycle ................................................................................... 71-
3
Outline of refrigerating cycle.................................................................................................................... 71-
4
Outline of main parts................................................................................................................................ 71-
6
Outline of control system ......................................................................................................................... 71- 10
Air conditioner
71-1
(6)
COMPARISON OF APPLICABLE MODELS AND AIR
STRUCTURE AND FUNCTIONCOMPARISON OF APPLICABLE
MODELS
AND AIR CONDITIONER UNITS
CONDITIONER
UNITS
COMPARISON OF APPLICABLE MODELS AND AIR
CONDITIONER UNITS
Note 1) Many machine models are equipped with air conditioners as shown below. For troubleshooting for different models, different wiring harness connectors are checked. The air conditioner units and control
units are basically the same, however.
Note 2) Some air conditioner units have different configurations, depending on the serial No. and type (automatic or manual) as shown below. They are basically the same, however.
The automatic air conditioners for PC78US-6 and PC128US-2 are used as examples for the following
explanation.
•
Applicable models
Standard machine models described
in this manual
Other hydraulic excavator models
(Having the same connectors)
1 Other hydraulic excavator models
for which this manual can be used
for reference
a Wiring harnesses are unknown
Other models for which this manual
can be used for reference
a Wiring harnesses are unknown
Part No. of air conditioner unit
2 Specification
•
PC78US-6
PC78US-6
PC78US-6
S/No. 4001 - 6500 S/No. 6501 and up S/No. 6501 and up
PC128US-2
PC128US-2
PC128US-2
S/No. 7301 - 9500 S/No. 9501 and up S/No. 9501 and up
PC78UU-6
PC78UU-6
PC78UU-6
PC138US-2
PC138US-2
PC138US-2
PC308US-3
PC228US-3
PC308US-3
CD110R-2
-
GD655-3
22B-979-1660
Common to automatic and manual
types
22U-979-1730
22U-979-1720
Special to
automatic type
Special to
manual type
Comparison of air conditioner units
Common to
Special to
Special to
automatic and
automatic type manual type
manual types
Different part
Part name
Part No.
Part No.
Part No.
Contents
1
Case assembly
534136-9921 534138-6620 534138-6620 Eliminate lining
2
534136-9321 534138-6720 534138-6720 from case and
wind onto evapora3
Evaporator assembly
503700-4760 503700-4770 503700-4770 tor
4
Pipe assembly
534057-3720 535237-9220 535237-9220 Add sight glass
Common to
automatic and
5
Wiring harness
536021-6501 536021-6501 536022-3500
3
manual types
6
Sensor (Internal air)
582623-8500 582623-8500 Eliminated
7
Bracket
534102-6000 534102-6000 Eliminated
8
Tapping screw
012514-1640 012514-1640 Eliminated
Sensor (Water temperature) 582623-1800 582623-1800 Eliminated
9
10
Clip
580529-7000 580529-7000 Eliminated
11
Screw
012155-1440 012155-1440 Eliminated
12
Insulator
583032-2300 583032-2300 Eliminated
Specification
71-2
(6)
Air conditioner
STRUCTURE AND FUNCTION
CONFIGURATION AND FUNCTIONS OF REFRIGERATING CYCLE
CONFIGURATION AND FUNCTIONS OF REFRIGERATING
CYCLE
Component
Compressor
Condenser
Expansion valve
Evaporator
Under operator's seat
(In air conditioner unit)
Makes refrigerant
liquid and gas of low
temperature which can
evaporate easily and
controls flow rate.
Under operator's seat
(In air conditioner unit)
Evaporates refrigerant
to absorb heat from
(or cool) air around
evaporator.
Item
Location
Function
Front of radiator in
many cases
Circulates refrigerant Condenses refrigerant
gas and increases its to discharge heat
temperature and
absorbed in evaporator.
pressure so that it can
be liquefied easily in
condenser.
Engine compartment
(Compression of
refrigerant)
State of
refrigerant
Gas
Gas
Adiabatic compression
(Condensation of refrig- (Restriction of refriger- (Evaporation of refrigerant)
ant)
erant)
Gas
Liquid
Constant pressure
change
Liquid
Liquid
Gas
Adiabatic expansion
Liquid
Gas
Gas
Constant pressure
change
6249
Air conditioner
71-3
(6)
STRUCTURE AND FUNCTION
OUTLINE OF REFRIGERATING CYCLE
OUTLINE OF REFRIGERATING CYCLE
The refrigerating cycle performs the following 4
actions and the refrigerant is liquefied and gasified
repeatedly while it is circuited in the cycle.
1. Compression (Compressor)
The refrigerant gas is compressed by the compressor to the state where it can be liquefied
easily at the normal temperature (ambient temperature).
The refrigerant evaporated in the evaporator is
sucked in the compressor.
This action is performed to keep the refrigerant
pressure in the evaporator low so that the refrigerant liquid can continue evaporation actively
even if the ambient temperature is close to 0°C.
The refrigerant gas sucked in the compressor is
compressed in the cylinder and its pressure and
temperature are so changed that it can be liquefied easily when it is cooled with the external air
at the normal temperature.
2. Condensation (Condenser)
The refrigerant gas in the condenser is cooled to
be liquefied with the external air.
The refrigerant gas of high temperature and high
pressure discharged from the compressor is
cooled to be liquefied with the external air and
then stored in the receiver drier.
The heat discharged from the refrigerant of high
temperature and high pressure discharged from
the compressor is called the condensation heat,
which is the total of the heat that the refrigerant
absorbed from the operator's cab through the
evaporator (vaporization heat) and the work performed to compress the refrigerant (the value
converted into heat).
During condensation, the refrigerant gas and
refrigerant liquid are mixed together in the condenser. While the refrigerant gas changes to the
refrigerant liquid, the relationship between the
pressure (condensation pressure) and temperature (condensation temperature) is kept constant.
3. Expansion (Expansion valve)
The pressure of the refrigerant liquid is lowered by
the restricting action of the expansion valve to a
level at which the refrigerant is evaporated easily.
The action to lower the pressure of the refrigerant to a level at which the refrigerant is evaporated easily before the refrigerant is sent to the
evaporator is called expansion.
The expansion valve which performs this action
also controls the flow rate of the refrigerant.
In other words, the quantity of the refrigerant liquid evaporated in the evaporator is decided by
the quantity of heat to be removed (refrigeration
load) at the specified evaporation temperature
(evaporation pressure), and the expansion valve
senses it and controls the refrigerant flow rate
properly.
[* 1] Restriction
If there is a sharply narrowed part in a pipe in
which a liquid is flowing, it is resistance to the
flow. Since the sectional area is increased
sharply after this part, the liquid expands quickly
and its pressure and temperature lower. No heat
is exchanged between the inside and outside of
the pipe during this action.
4. Evaporation (Evaporator)
The refrigerant changes from liquid to gas
(superheated vapor) in the evaporator.
The refrigerant mist in the evaporator evaporates actively.
At this time, the refrigerant evaporates quickly,
absorbing heat necessary for evaporation (latent
heat of vaporization) from the air around the
cooling fins (air in the operator's cab). The
cooled air is spread in the operator's cab by the
fan to lower the temperature in the operator's
cab.
Reference: The pressure varies with the type of
the refrigerant and condensation
temperature.
71-4
(6)
Air conditioner
STRUCTURE AND FUNCTION
The refrigerating cycle performs
theOF
following
4 actions and
the
OUTLINE
REFRIGERATING
CYCLE
The refrigerant mist sent through the expansion
valve and the evaporated refrigerant are mixed
together in the evaporator. While the refrigerant
liquid changes to the refrigerant gas, the relationship between the pressure (evaporation
pressure) and temperature (evaporation temperature) is kept constant. If the pressure is set, the
temperature is decided automatically.
That is, the relationship between the above pressure and temperature is equal to the relationship
between saturation pressure and saturation temperature.
To evaporate the refrigerant at lower temperature, the pressure in the evaporator must be kept
lower.
Accordingly, the evaporated refrigerant is
sucked in the compressor.
The refrigerant circulates in the refrigerating
cycle, repeating the above 4 actions, to move
the heat from the operator's cab where the temperature is low to the outside where the temperature is high.
Air conditioner
71-5
(6)
STRUCTURE AND FUNCTION
OUTLINE OF MAIN PARTS
OUTLINE OF MAIN PARTS
1. Compressor assembly
1) Compressor
The compressor is of swash plate type.
The swash plate is installed to the shaft. The
rotary motion of the shaft is converted into
the reciprocating motion to suck, compress,
and discharge the refrigerant.
2) Magnet clutch
The magnet clutch is used to drive or stop
the compressor while the engine is running.
While the compressor is not driven, only the
pulley is revolving.
When the compressor is driven, a current
flows in the field coil to make a strong electromagnet, which attracts the drive plate to
rotate the compressor shaft and the pulley
together.
3) Relief valve (Installed to only PC1238US-2)
When the pressure in the compressor
exceeds the set pressure of the relief pressure, the relief valve opens to discharge the
refrigerant. If the pressure lowers, the relief
valve closes.
9JS01940
2. Condenser
The condenser is of parallel flow type.
The refrigerant gas of high temperature and high
pressure sent from the compressor is cooled to
be liquefied with the cooling fan of the engine.
a PC128US-2 has a sub-cool condenser made
one with the receiver drier.
9JS01941
3. Receiver drier
The receiver drier is of aluminum flat head type.
The receiver drier has the following functions.
q The receiver drier stores the refrigerant to
operate the cooling cycle smoothly.
q The receiver drier removes dirt and water
from the refrigerant.
q Flowing condition of the refrigerant is seen
through the sight glass.
q If the temperature of the cycle rises for some
reason, the lead at the center of the fusible
plug melts and the refrigerant is discharged
out to secure the safety.
71-6
(6)
6250
Air conditioner
STRUCTURE AND FUNCTION
•
OUTLINE OF MAIN PARTS
The main parts under the operator's seat are roughly classified into air conditioner unit (1), intake duct (2),
and mode duct (3).
9JS01943
4. Intake duct (2)
The intake duct selects the external air or internal air to be sucked in the fan motor of the air
conditioner unit.
Filter (4) is installed to the air outlet side of the
intake box to remove dust from the external air
and internal air and supply clean air to the air
conditioner unit. The intake duct includes the
intake actuator and intake door.
5. Mode duct (3)
The mode duct changes the flow of the air
cooled with the evaporator of the air conditioner
unit, air heated with the heater core, or mixture
of the cooled air and heated air to each air outlet.
There are 3 selectable positions and the operator can select a favorite flow with the control
panel.
The mode duct includes the mode actuator and
mode door.
6. Air conditioner unit (1)
The air conditioner unit includes the blower
motor, evaporator, heater core, mix door, and
internal air filter (5). Its piping has the pressure
switch for protection and the sight glass to check
the refrigerant. It is thin and compact and has a
connecting hole to take in external air.
Air conditioner
71-7
(6)
STRUCTURE AND FUNCTION
1) Expansion valve
The expansion valve is of internal equal pressure type.
The expansion valve converts the high pressure
refrigerant liquid sent from the receiver drier into
low pressure refrigerant mist by restricting action
and sends it to the evaporator.
The expansion valve also adjusts the refrigerant
flow rate automatically according to the variable
thermal load.
2) Evaporator
The evaporator is of serpentine type.
The refrigerant mist made by the expansion
valve evaporates actively in the evaporator and
its temperature lowers.
The air in the operator's cab is sucked in the fan
and passed and cooled through the evaporator.
3) Thermostat
The thermostat senses the temperature of the
cooled air just after it is blown out of the evaporator and turns the compressor OFF before the
evaporator is frozen.
a If the thermostat does not touch the evaporator, it cannot sense the temperature and
cooling does not stop. As a result, evaporator is frosted and air flow rate is lowered.
OUTLINE OF MAIN PARTS
6251
6252
4) Pressure switch
The pressure switch senses abnormally low or
high pressure and turns the compressor OFF.
k When replacing the pressure switch, collect the
refrigerant in advance.
6253
71-8
(6)
Air conditioner
STRUCTURE AND FUNCTION
Pressure
OUTLINE OF MAIN PARTS
Between terminals
Max. approx. 0.177 MPa
{1.8 kg/cm2}, Min. approx. There is not continuity
2.65 MPa {27 kg/cm2}
Between approx.
0.177 and 2.65 MPa
{1.8 - 27 kg/cm2}
There is continuity
5) Fan motor
A sirocco fan is used to lower the noise.
9JS01947
6) Heater core
The hot water from the engine cooling water
(hot) outlet flows in the heater core, where it
heats the air sent by the fan motor.
9JS01948
Air conditioner
71-9
(6)
STRUCTURE AND FUNCTION
OUTLINE OF CONTROL SYSTEM
OUTLINE OF CONTROL SYSTEM
The control panel is installed to the top of the control unit. It receives various signals and indicates them with
the LED and controls the air conditioner unit, actuators of 3 types, and compressor.
9JS02164
71-10
(6)
Air conditioner
STRUCTURE AND FUNCTION
•
•
OUTLINE OF CONTROL SYSTEM
Configuration of control panel and air conditioner unit
The relationship between the switches on the control panel (top of the control unit) and the actuators of the
air conditioner unit is shown by [1] - [5] in the following figures.
Control panel
a The control panel shown below is for the automatic air conditioner.
6254
•
Configuration of air conditioner unit
6255
Air conditioner
71-11
(6)
TESTING AND ADJUSTING
TESTING AND ADJUSTING
ZEXEL VALEO (NEW REFRIGERANT (R134a) TYPE)
List of tools for testing, adjusting, and trouble shooting ......................................................................... 72-
2
Inspection and maintenance table for air conditioner ............................................................................ 72-
3
Inspection and maintenance table for heater ........................................................................................ 72-
4
Inspection with self-diagnosis function .................................................................................................. 72-
5
Outline ....................................................................................................................................... 72-
5
Self-diagnosis procedure ........................................................................................................... 72-
6
Step 1 inspection of display unit and display led ...................................................................... 72-
7
Step 2 inspection of each sensor and actuator ........................................................................ 72-
8
Step 3 display of past troubles ................................................................................................. 72-
9
Step 4 inspection of each output device ................................................................................... 72- 10
Step 5 set temperature correcting function .............................................................................. 72- 11
Inspecting temperature adjustment (air mix door and mix actuator) ..................................................... 72- 12
Inspecting selection of air outlet (mode door and mode actuator) ......................................................... 72- 13
Inspecting selection of intake (intake door and intake actuator) ............................................................ 72- 13
Inspecting relays .................................................................................................................................... 72- 14
Checking for refrigerant leakage ........................................................................................................... 72- 15
Charging with refrigerant ....................................................................................................................... 72- 18
Handling refrigerant can and compressor oil ......................................................................................... 72- 19
Precautions for connecting air conditioner piping .................................................................................. 72- 22
Air conditioner
72-1
(6)
LIST OF TOOLS FOR TESTING, ADJUSTING, AND TROUBLELIST OF TOOLS
FOR TESTING, ADJUSTING, AND TROUBLESHOOTING
SHOOTING
TESTING AND ADJUSTING
LIST OF TOOLS FOR TESTING, ADJUSTING, AND TROUBLESHOOTING
Testing and adjusting
item
Symbol
Part No.
Part name
1 799-703-1200 Service tool kit
Measuring refrigerant
pressure in air conditioner, charging with
refrigerant, and discharging refrigerant
799-703-1100 Vacuum pump
N
2 799-703-1111 Vacuum pump
799-703-1121 Vacuum pump
Leakage of refrigerant
72-2
(6)
O
799-703-1400 Gas leak tester
Remarks
For new refrigerant R134a
For new refrigerant R134a in Japan
(100 V)
For new refrigerant R134a in overseas countries (220 V)
For new refrigerant R134a in overseas countries (240 V)
For countries other than USA
Air conditioner
TESTING AND ADJUSTING
INSPECTION AND MAINTENANCE TABLE FOR AIR
INSPECTION AND
MAINTENANCE TABLE FOR AIR CONDITIONER
CONDITIONER
The air conditioner (cooler/heater) needs "periodic
inspection and maintenance" (there is a charge for
it) for constant use under the best condition.
If the air conditioner has a trouble, much repair cost
is required. Accordingly, recommend that the customer should take periodic inspection and maintenance.
INSPECTION AND MAINTENANCE TABLE FOR AIR CONDITIONER
No.
Inspection item
Contents of inspection
Maintenance
Inspection/Maintenance
period (interval)
6
12
24
36
months months months months
1 Start and stop
Flow of cold air
Q
2 Refrigerant and pressure
Quantity of refrigerant and
gauge pressure
Q
3 Condenser
Stain and clogging
4 Condenser fan motor
Operating condition
5 Belt
Tension, flaw, and deterioration Adjust or replace
Q
6 Air filter
Stain, clogging, and removal Adjust or replace
aQ
7 Clean or replace
Stain, clogging, and removal Adjust or replace
aQ
8 Piping and its connections
Refrigerant leakage
Clean
Q
Q
leakage, loose9 Cycle parts and their mounting parts Refrigerant
ness, and breakage
between cycle parts Clearance
10 Clearance
and machine parts
aQ
Q
Secure clearance
Q
If defective, replace
Q
11 Pressure switch
OFF when high pressure is above
2,648 kPa {27 kg/cm2G}
OFF when high pressure is below
176 kPa {1.8 kg/cm2G}
12 Compressor
Operating condition
Q
w
13 Valve of compressor
Breakage
Q
w
14 Bearing of compressor
Q
w
15
Q
16
17
18
Operating condition (Abnormal sound)
Operating condition and wear
Magnet clutch
of attracting surface
Operating condition (AbnorBearing of magnet clutch
mal sound)
Operating condition (AbnorTension pulley
mal sound)
High pressure and low pressure hoses Flaw, deterioration, and
breakage
Q
Q
Q
19 Air conditioner unit (Evaporator) Stain, clogging, and breakage If clogged, disassemble
Q
20 Electric parts and their wiring Operating condition and breakage
Q
21 Receiver drier
Clogging and breakage
22 Expansion valve
Operating condition
Q
q
Q
w
23 Compressor assembly
a Daily inspection. Q Inspection. w Disassembly. q Replacement
Advice
qInspect the belt at intervals of 6 months or about 50 operating hours.
qDirect the customer to inspect the items marked with a every day.
Air conditioner
72-3
(6)
TESTING AND ADJUSTING
INSPECTION AND MAINTENANCE TABLE FOR HEATER
INSPECTION AND MAINTENANCE TABLE FOR HEATER
No.
Inspection item
Contents
of inspection
Maintenance
Inspection/Maintenance
period (interval)
6 months
1
Start and stop
Flow of hot air
Q
2
Engine coolant
Coolant level
Q
3
Piping and its connections
Water leakage and
clamping condition
Water leakage, looseness, and breakage
Q
4
5
Cycle parts and their mounting
parts
Clearance between cycle parts
and machine parts
12 months
Q
Q
Clearance
6
Heater hose
Flaw, deterioration,
and breakage
Q
7
Fan motor
Operating condition
Q
8
Air conditioner unit (Heater core) Stain and clogging
9
Electric parts and their wiring
Operating condition
and breakage
If clogged, disassemble
Q
Q
Q Inspection
72-4
(6)
Air conditioner
TESTING AND ADJUSTING
INSPECTION WITH SELF-DIAGNOSIS FUNCTION
INSPECTION WITH SELF-DIAGNOSIS FUNCTION
1. Outline
•
There are steps 1 - 5 in the self-diagnosis. You can check each sensor (which is not installed to the air conditioner having only the manual mode) for trouble according to those steps. You can also output control signals specified for each output device and inspect the operation of the device (excluding the intake
actuator). If a troubled section is detected, every part of that section must be inspected.
Step 1
Step 2
Step 3
Step 4
Step 5
•
Starting self-diagnosis mode
1) Turn the air conditioner OFF.
2) While pressing the air conditioner switch and foot switch, turn the key switch from the OFF position to
the START position to start the engine, and the self-diagnosis (step 1) starts.
Note:
•
Inspection of display unit and display LED
Inspection of each sensor and actuator (excluding intake actuator)
Each sensor, mix actuator, and mode actuator are inspected in real time.
Display of past troubles
The recorded past troubles of each sensor, mix actuator, and mode actuator are displayed.
Inspection of each output device
The pattern operation of each output device is performed.
Set temperature correcting function
If the battery voltage lowers below 24V during step 4, the operating speed of the actuator lowers.
As a result, the actuator may be judged NG, even if it is operating normally. Accordingly, start the
engine when performing the self-diagnosis.
Finishing self-diagnosis
1) Turn the key switch OFF.
2) Hold the OFF switch for 3 seconds.
a Selecting a step
• Select step 1 - 5 with the fan switch.
6256(6)
Air conditioner
72-5
(6)
TESTING AND ADJUSTING
INSPECTION WITH SELF-DIAGNOSIS FUNCTION
2. Self-diagnosis procedure
Outline
6257(7)
72-6
(6)
Air conditioner
TESTING AND ADJUSTING
INSPECTION WITH SELF-DIAGNOSIS FUNCTION
3. Step 1 Inspection of display unit and display LED
The display LED of each switch on the panel is inspected.
All of the LEDs flash in the following order. (Up to 6 LEDs flash simultaneously.)
If normal, each LED is turned ON and OFF twice at intervals of 0.5 seconds in the flashing period.
Display order of LED
Note) -- means that LED is turned OFF.
Display
Same operation is
repeated
STEP 1
STEP 2
STEP 3
STEP 4
STEP 1
•••
A/C
Flashing
Flashing
Flashing
Flashing
Flashing
Flashing
Front/Rear vent
Flashing
--
--
--
Flashing
--
Rear vent
--
Flashing
--
--
--
Flashing
Foot
--
--
Flashing
--
--
--
AUTO
Flashing
Flashing
Flashing
Flashing
Flashing
Flashing
LO
Flashing
--
--
--
--
Flashing
ML
--
Flashing
--
--
--
--
MH
--
--
Flashing
--
--
--
HI
--
--
--
Flashing
--
--
TEMP 1
Flashing
--
--
--
Flashing
--
TEMP 2
--
Flashing
--
--
--
Flashing
TEMP 3
--
--
Flashing
--
--
--
TEMP 4
--
--
--
Flashing
--
--
TEMP 5
Flashing
--
--
--
Flashing
--
TEMP 6
--
Flashing
--
--
--
Flashing
TEMP 7
--
--
Flashing
--
--
--
TEMP 8
--
--
--
Flashing
--
--
LED
When normal:
All the display LEDs light up.
When abnormal:
The LED of a troubled section does not light up.
Is the display LED normal?
YES > Go to step 2
NO
> Replace the control unit.
Air conditioner
72-7
(6)
TESTING AND ADJUSTING
INSPECTION WITH SELF-DIAGNOSIS FUNCTION
4. Step 2 Inspection of each sensor and actuator
1. Press the fan UP switch to select step 2.
2. During step 2, the front/rear vent LED flashes. After the inspection is finished, the front/rear vent LED
lights up.
When normal:
Only front/rear vent LEDs lights up.
When abnormal: Front/rear vent LEDs lights up and TEMP LED flashes.
After operation is confirmed, each output returns to the initial position.
How is the inspection result?
OK
> Go to step 3
NG
> See the following
Inspection of troubled sensor and actuator
If a sensor or an actuator is troubled, the TEMP LED corresponding to it flashes.
If multiple sensors or actuators are troubled, the LED flashes twice at intervals of 0.5 seconds, and then the
next trouble is displayed.
Contents of display by LED
Object of diagnosis
Location of display LED
Reference section
Mix actuator
TEMP 1
Inspecting temperature adjustment (Air mix
door and mix actuator) (Page 72-12)
Mode actuator
TEMP 2
Inspecting selection of air outlet (Mode door
and mode actuator) (Page 72-13)
Internal air sensor (* 1)
TEMP 3
Troubleshooting, How to inspect electric
parts, internal air sensor (Page 73-8)
External air sensor (* 1)
TEMP 4
Troubleshooting, How to inspect electric
parts, external air sensor (Page 73-8)
Water temperature sensor (* 1)
TEMP 5
Troubleshooting, How to inspect electric
parts, water temperature sensor (Page 73-8)
Sunlight sensor (* 1)
TEMP 6
Troubleshooting, How to inspect electric
parts, sunlight sensor (Page 73-8)
Caution: While the sunlight sensor is not exposed to the sunlight, a trouble is displayed.
• Not installed to the air conditioner having only manual mode. (* 1)
• The external air sensor is not installed to the automatic air conditioner of PC78US-6, either.
72-8
(6)
Air conditioner
TESTING AND ADJUSTING
INSPECTION WITH SELF-DIAGNOSIS FUNCTION
5. Step 3 Display of past troubles
1) Press the fan UP switch to select step 3.
2) During step 3, the front/rear vent LED flashes. After the inspection is finished, the front/rear vent LED
lights up.
If there is not a past trouble: Only front/rear vent LEDs lights up.
If there is any past trouble: Front/rear vent LEDs lights up and TEMP LED flashes.
How is the inspection result?
OK
> Go to step 4
NG
> See the following
Inspection of past trouble of sensor and actuator
If a sensor or an actuator has been troubled, the TEMP LED corresponding to it flashes.
If multiple sensors or actuators have been troubled, the LED flashes twice at intervals of 0.5 seconds, and then
the next trouble is displayed.
Contents of display by LED
Object of diagnosis
Location of display LED
Mix actuator
TEMP 1
Mode actuator
TEMP 2
Internal air sensor ( * 1 )
TEMP 3
External air sensor ( * 1 )
TEMP 4
Water temperature sensor ( * 1 )
TEMP 5
Sunlight sensor ( * 1 )
TEMP 6
Caution: As trouble of the sunlight sensor, only short circuit is recorded.
• Not installed to the air conditioner having only manual mode. ( * 1 )
• The external air sensor is not installed to the automatic air conditioner of PC78US-6, either.
How to delete past trouble record
Hold the air conditioner switch for 3 seconds in step 3, and the past trouble record is deleted. At this time,
the air conditioner LED flashes 5 times, and then it returns to the normal control mode.
Each switch is initialized.
Air conditioner
72-9
(6)
TESTING AND ADJUSTING
INSPECTION WITH SELF-DIAGNOSIS FUNCTION
6. Step 4 Inspection of each output device
1) Press the fan UP switch to select step 4.
2) Each time the foot switch is pressed, TEMP LEDs light up one by one from the left to the right.
3) Inspect the air outlet, spurting air temperature, voltage applied to the blower fan motor, and operation
of the compressor (magnet clutch).
Same operation is repeated
STEP
Objective device
1
2
3
4
TEMP 1
TEMP 2
TEMP 3
TEMP 4
Front/Rear
vent
Rear vent
Rear vent
Foot
Opening ratio of air mix door
Full cool
50%
50%
Full heat
Voltage applied to blower fan
motor
10V
14.5
19.5
Source
voltage
Compressor (Magnet clutch)
ON
ON
ON
OFF
Lighting of LED
Mode door
1 ••••
How is the inspection result?
OK
> Finish self-diagnosis
NG
> • The air outlet does not change: See Inspecting selection of air outlet. (Mode door and mode actuator)
• The spurting air temperature does not change: See Inspecting temperature adjustment. (Air mix
door and mix actuator)
• Defective operation of blower fan motor: See Troubleshooting table
• Defective operation of compressor: See Troubleshooting table
72-10
(6)
Air conditioner
TESTING AND ADJUSTING
INSPECTION WITH SELF-DIAGNOSIS FUNCTION
7. Step 5 Set temperature correcting function (Function of setting difference between set temperature and control temperature)
Outline
When the set spurting air temperature is different from the sensory temperature, you can change the control temperature of the control unit from the set (displayed) temperature.
Method
1) Select the self-diagnosis mode.
2) In self-diagnosis step 4, press the fan UP switch and AUTO switch simultaneously.
3) The temperature setting LEDs (2 pieces at the center) light up.
4) Each time the temperature setting switch (UP or DOWN) is pressed, a different temperature setting
LED lights up and you can set the correction temperature freely between +2 °C and -2 °C.
6258(3)
Reference: If the correction temperature is set while the leftmost temperature setting LED (-2 °C) is lighting,
the control unit controls the temperature to 25 °C - 2 °C = 23 °C. Accordingly, the actual temperature is controlled below the displayed temperature.
Caution: If the negative terminal of the battery is disconnected or the battery voltage lowers below 20V,
the difference between the set (displayed) temperature and control temperature is cancelled.
Air conditioner
72-11
(6)
INSPECTING TEMPERATURE ADJUSTMENT (AIR MIX DOOR
TESTING AND ADJUSTING INSPECTING TEMPERATURE
ADJUSTMENT (AIR MIX DOOR AND MIX ACAND MIX ACTUATOR)
INSPECTING TEMPERATURE ADJUSTMENT (AIR MIX DOOR
AND MIX ACTUATOR)
•
If a mix actuator error is detected by the self-diagnosis, inspect the mix actuator visually.
1. Remove operator's seat undercover (1).
2. Turn the starting switch ON (and start the
engine) and operate the temperature setting
switch of the control panel from the left end (FC)
to the right end (FH) to see if levers 1 and 2
operate in 8 steps.
AJS01467
a If the result is NG, see Troubleshooting, E-4 Temperature cannot be adjusted
6254
•
Front side of air conditioner unit under operator's seat
9JS02169
72-12
(6)
Air conditioner
INSPECTING SELECTION OF AIR OUTLET (MODE DOOR AND MODE ACTUATOR)
TESTING AND ADJUSTINGINSPECTING
SELECTION
OFOFAIR
OUTLET
(MODE
DOOR
AND MODE
ACTUINSPECTING
SELECTION
INTAKE
(INTAKE
DOOR
AND INTAKE
ACTUATOR)
INSPECTING SELECTION OF AIR OUTLET (MODE DOOR AND
MODE ACTUATOR)
•
1.
2.
3.
4.
5.
a
If a mode actuator error is detected by the selfdiagnosis, inspect the mode actuator visually.
Remove monitor panel under cover (1).
Loosen right console (2) and move it inward, and
then remove cover (3).
Disconnect connector M88, move duct joint A in
the direction of the arrow, and then remove
mode duct (5) toward you (so that you can see
inside)
Connect connector M88 and turn the starting
switch ON (and start the engine).
Operate the mode switch of the control panel to
see if mode door (4) operates normally.
If the result is NG, see Troubleshooting, Troubleshooting for selection of air outlet (Mode door
and mode actuator)
AJS01468
INSPECTING SELECTION OF INTAKE (INTAKE DOOR AND
INTAKE ACTUATOR)
•
Since selection of the intake cannot be inspected
by the self-diagnosis, inspect it according to the
following procedure.
1. Disconnect M83 from under the rear left of the
operator's seat and remove intake duct (1).
2. Make the internal intake door visible, connect
connector M83, and turn the starting switch ON
(and start the engine).
3. Operate the intake switch of the control panel to
see if the intake door operates normally.
a If the result is NG, see Troubleshooting,
Troubleshooting for selection of intake
(intake door and intake actuator)
AJS01469
6254
Air conditioner
72-13
(6)
TESTING AND ADJUSTING
INSPECTING RELAYS
INSPECTING RELAYS
a If the compressor revolves and air spurts to the
maximum level, the relays are normal. Omit the
following inspection, in this case.
Inspect the relays of 3 types by sound. (If each
relay is normal, it clicks when it is turned ON and
OFF.)
a Bring your ear close to each relay and hear it
clicks.
•
•
•
AJS01467
Air conditioner relay: Turning ON/OFF of compressor
OFF relay: Turning ON/OFF of fan motor
MAX HI relay: Turning ON when air flow is at
maximum
1. Remove operator's seat undercover (1).
9JS02180
2. While the starting switch is turned OFF, disconnect pressure switch connector (I) and fan motor
connector (O) (to prevent the compressor and
fan motor from starting)
3. Turn the starting switch ON (Do not start the
engine, however) and turned the air conditioner
switch of the control panel ON/OFF to check that
the relays make sound.
a The air conditioner relay and OFF relay
sounds independently, thus the sound is
made twice. If the sound is made only once,
turn the starting switch OFF and remove
either relay to see with relay is broken.
4. Set the fan motor speed between the maximum
and medium to check that the MAX HI relay
makes sound.
72-14
(6)
Air conditioner
TESTING AND ADJUSTING
CHECKING FOR REFRIGERANT LEAKAGE
CHECKING FOR REFRIGERANT LEAKAGE
Since refrigerant leakage has bad effects on the performance and durability of the air conditioner and
global environment, it must be stopped immediately,
if detected.
Flow of checking for refrigerant leakage
6259(26)
1. Checking for refrigerant leakage
Using a special gas leak detector for HFC-134a,
check for refrigerant leakage. If any troubled part
is found, repair it.
In this case, repeat the procedure from the first
step.
k Caution
Never use a CFC-12R (R-12) leak detector of
halide torch type to check for refrigerant leakage.
The leak detector of halide torch type detects
CFC-12 leakage by reacting on chlorine contained in CFC-12.
Since HFC-134a does not contain chlorine, the
leak detector of halide type cannot detect it. In
addition, if HFC-134a come in contact with
flame, it is decomposed and poisonous gas is
produced.
Air conditioner
6260(3)
72-15
(6)
TESTING AND ADJUSTING
Check for refrigerant leakage according to the
following procedure.
a Before starting the check, confirm that there is
no refrigerant or smoke around the machine to
prevent misjudgment of refrigerant leakage.
Perform the check in a place where leaking
refrigerant will not be blown off by wind.
a Perform the check mainly on pipe joints and
parts which are stained oil remarkably.
If refrigerant leaks, internal oil always leaks, too.
CHECKING FOR REFRIGERANT LEAKAGE
•
When leakage is not detected by the ordinary
check, operate the compressor for at least 5
minutes and then check the high pressure side
similarly.
a After the compressor is stopped, the high pressure lowers gradually. Refrigerant leakage from
the high pressure side can be detected easily
while the pressure is higher.
Accordingly, operate the compressor. Immediately after stopping the engine, check the highpressure parts immediately for refrigerant leakage with the gas leak detector.
6261(2)
•
72-16
(6)
6262(2)
Air conditioner
TESTING AND ADJUSTING
•
CHECKING FOR REFRIGERANT LEAKAGE
Important parts to be checked for refrigerant leakage
Part name
Check point
Compressor
Pipe joints
Shaft seals
Cylinder fitting parts
Condenser
Pipe joints
Welded parts of body
Receiver drier
Pipe joints
Dual pressure switch
Fusible plug
Around sight glass
Air conditioner unit
Pipe joints
Expansion valve joints
Brazed parts of evaporator
Remarks
Check through clearance of magnet clutch
Check through hole for drain hose
Pipe joints
Piping (Hoses and pipes) Caulked parts of hoses
Hoses and pipes
Service valve
Around service valve
Install a cap when checking
2. Adding refrigerant
• Referring to 42-11, Connecting service tool prepared by DENSO CO., LTD. (New refrigerant specifica
tion), connect the gauge manifold.
• To make sure, perform 42-19, Checking with gauge manifold.
• Add refrigerant. See 42-38, Charging with (Adding) refrigerant from low pressure side.
kSince refrigerant is high-pressure gas, it must be handled by only designated persons.
kIf refrigerant gets in your eyes, you may lose your sight. (Put on protective goggles.)
3. After adding refrigerant, perform the final refrigerant leakage test.
Air conditioner
72-17
(6)
TESTING AND ADJUSTING
CHARGING WITH REFRIGERANT
CHARGING WITH REFRIGERANT
See 42-32, Charging with refrigerant (New refrigerant specification) prepared by DENSO CO., LTD
k Since refrigerant is high-pressure gas, it must be handled by only designated persons.
k If refrigerant gets in your eyes, you may lose your sight. (Put on protective goggles.)
72-18
(6)
Air conditioner
TESTING AND ADJUSTING
HANDLING REFRIGERANT CAN AND COMPRESSOR OIL
HANDLING REFRIGERANT CAN AND COMPRESSOR OIL
1. Refrigerant can (HFC-134a) (For repair)
a HFC-134a and R134a are the same material.
Quantity of
refrigerant
Part No.
200g
583200-0600
a The label and the adapter thread size of the
refrigerant can valve are different from those of
the CFC-12 can for distinction.
2. Precautions for storing and handling refrigerant can
When handling the refrigerant can, observe the
precautions printed on it.
q Do not store the refrigerant can in place
where the temperature is heightened above
40°C by the direct sunlight, fire, etc.
q Be sure to store the refrigerant can in a dark
and cool place. Do not corrode it.
q Carry the minimum necessary quantity of
refrigerant cans and keep them in a place
where the temperature does not rise above
40°C.
9JS02187
kThe high-pressure gas is in the refrigerant
can. If the can is stored in a hot place, its
inside pressure rises and it may burst and
can cause injury, frostbite, loss of sight, etc.
q Never throw or hit the refrigerant can. (Do
not roughly handle the package of the refrigerant can, either.)
q If the refrigerant can has a flow, bruise, etc.,
do not use it.
kThe high-pressure gas is in the refrigerant
can. If the can is handled wrongly, it may
burst or the refrigerant may leak, and that
can cause injury, frostbite, loss of sight, etc.
q Do not put the refrigerant can in fire.
kDo not bring refrigerant in contact with flame.
If refrigerant touches flame, it will be decomposed and poisonous gas will be produced.
q Keep the refrigerant can off children.
Air conditioner
72-19
(6)
TESTING AND ADJUSTING
HANDLING REFRIGERANT CAN AND COMPRESSOR OIL
3. Control of compressor oil (ZXL-100PG: For
HFC134a)
Compressor oil does not need to be checked or
added so frequently as engine oil. Insufficiency
or excess of compressor oil can cause the following troubles, however.
Accordingly, compressor oil must be supplied to
the specified level, similarly to refrigerant.
Check compressor oil in the following cases, and
then add new oil if necessary.
q At the beginning of the 2nd season.
q When much refrigerant is discharged
because of leakage.
q When the compressor is troubled and
replaced.
q When a cycle parts such as the condenser,
receiver drier, evaporator unit, etc. is
replaced.
Condition
Insufficiency of oil
Excess of oil
•
added
Air conditioner part Quantity to be
(cm3)
Evaporator
Approx. 50
Condenser
Approx. 30
Receiver drier
Approx. 50
Hose/Pipe
Approx. 10
<Oil return operation>
Item
5. Oil return operation
Compressor oil is circulated in the air conditioner
cycle together with refrigerant while the air conditioner is in operation.
When checking the oil level or replacing a cycle
part, you are required to return compressor oil in
the piping and each component part to the compressor to minimize the quantity of oil lost during
the replacement work. For this purpose, perform
the "oil return operation" shown at right.
a If it is impossible to perform the oil return
operation (because of seizure, breakage,
etc.), install a new compressor (link part,
etc.) and perform the oil return operation.
Then, remove the compressor again and
drain the excessive oil.
72-20
(6)
Lubrication trouble and
seizure of compressor
Cooling trouble (Excessive
oil stick to parts and lower
heat exchange performance)
Quantity of oil to be added when cycle
part is replaced
4. Procedure for checking (adding, replacing)
oil level
1) Perform the oil return operation.
2) Collect refrigerant in the air conditioner
cycle. [* 1]
3) Remove the compressor.
4) Check the oil level.
5) Add or replace oil.
6) Install the compressor.
7) Charge the air conditioner cycle with refrigerant. [* 2]
[* 1] [* 2] TAKAHASHI WORKS CO., LTD., see page
52 - 3 to 15.
kSince refrigerant is high-pressure
gas, it must be handled by only
designated persons.
kIf refrigerant gets in your eyes,
you may lose your sight. (Put on
protective goggles.)
Contents
Condition value
Doors
Open all doors (OPEN)
Engine speed
Approx. 1,000 rpm
Blower fan motor
HI (Max. speed)
Air conditioner switch
ON (Operate compressor)
Operating time
Approx. 20 min
Air conditioner
TESTING AND ADJUSTING
HANDLING REFRIGERANT CAN AND COMPRESSOR OIL
6. Draining and adding compressor oil
1) Draining oil.
Prepare an oil pan and drain oil.
Measure the quantity of the drained oil with a
measuring cylinder and set it as the
16quantity to be added.
a The type (ZXL-100PG) and additional quantity of compressor oil are printed on the label
stuck to the compressor.
2186(2)
2) Adding oil
Add oil of the specified quantity (quantity
measured with the measuring cylinder)
through the port in the reverse order to draining.
a If oil for CFC-12 (R-12) is used, lubrication
trouble will occur and the compressor may
be broken or seized.
Be sure to use the specified oil (ZXL-100PG).
a Oil for HFC-134a absorbs moisture very easily. Accordingly, fit the cap immediately after
using oil to stop the atmosphere.
Store the oil can in a dry and ventilated place.
2187(2)
a Precautions for using oil
Oil for HFC-134a (ZXL-100PG in particular)
may dissolve acrylic resin and polystyrene
(excluding baked polystyrene paint film).
Accordingly, do not stick oil to those plastics.
2188(2)
7. Compressor oil for applying piping
When connecting a pipe or hose, apply oil (ZXL100PG) to its O-ring to prevent refrigerant leakage.
kWhen discarding a can which still has some
oil in it, make a hole on it to discharge gas
and oil.
Air conditioner
2189(2)
72-21
(6)
TESTING AND ADJUSTING
PRECAUTIONS FOR CONNECTING AIR CONDITIONER PIPING
PRECAUTIONS FOR CONNECTING AIR CONDITIONER PIPING
q When connecting the piping, apply compressor
oil to the O-rings. (See the previous page.)
Do not apply oil to the threads of a nut or union,
however.
q Once an O-ring is used, it is deformed and deteriorated. Accordingly, do not reuse it. When
removing it, use a soft tool (such as a toothpick)
so that the piping will not be damaged.
q Push in each pipe to the stopper (until it clicks)
and tighten the nut fully with your fingers.
q Be sure to use 2 wrenches to tighten each nut
(Apply a torque wrench to the tightening side).
Fix 1 wrench and tighten the nut with another
wrench to the specified torque.
a Tightening torque for pipes of O-ring type
(Standard value)
Tightening torque
Outside
Nm {kgm}
diameter of pipe
Cylindrical
(mm)
End face seal
face seal
72-22
(6)
ø 8, ø 9
9.8 – 20
{1.0 – 2.0}
9.8 – 20
{1.0 – 2.0}
ø 12
15 – 25
{1.5 – 2.5}
15 – 25
{1.5 – 2.5}
ø 16
20 – 29
{2.0 – 3.0}
29 – 34
{3.0 – 3.5}
ø 19
25 – 34
{2.5 – 3.5}
34 – 49
{3.5 – 4.0}
Air conditioner
TROUBLESHOOTING
ZEXEL VALEO (NEW REFRIGERANT (R134a) TYPE)
Troubleshooting procedure...................................................................................................................... 73-
2
Block diagram and circuit diagram of control system .............................................................................. 73-
3
Detail of air conditioner unit ..................................................................................................................... 73-
5
Arrangement of connector pins ............................................................................................................... 73-
6
Arrangement of connectors and how to disconnect control unit connectors ........................................... 73-
7
How to inspect electric parts.................................................................................................................... 73-
8
Troubleshooting chart .............................................................................................................................. 73- 10
Troubleshooting table ...............................................................................................................................73- 11
Troubleshooting for electrical system (E mode) ...................................................................................... 73- 13
E-1 Air conditioner does not operate............................................................................................ 73- 14
E-2 Air is not cooled ..................................................................................................................... 73- 16
E-3 Air does not come out or air flow is abnormal........................................................................ 73- 18
E-4 Temperature cannot be adjusted ........................................................................................... 73- 20
E-5 Air outlet cannot be changed ................................................................................................. 73- 22
E-6 Intake cannot be changed ..................................................................................................... 73- 25
Troubleshooting with gauge pressure...................................................................................................... 73- 26
Air conditioner
73-1
(6)
TROUBLESHOOTING
TROUBLESHOOTING PROCEDURE
The air conditioner has a self-diagnosis function for inspecting the main component parts. With this function,
you can inspect the operations of each sensor (which is not installed to the air conditioner having only the manual mode), each actuator, and fan motor system.
If a troubled section is detected, every part of that section must be inspected.
TROUBLESHOOTING PROCEDURE
1. Find out the troubled section according to the detected trouble of the air conditioner.
2. Find out the troubled section with the self-diagnosis function (See TESTING AND ADJUSTING, Inspection
with self-diagnosis).
If the air conditioner unit or control unit does not operate at all, however, check that the power supply up to
the control unit is normal.
If any part of the air conditioner unit or control unit operates, the power supply does not need to be
checked.
3. After finding out the troubled section, inspect the component parts in that section and repair the troubled
part.
Basic flow of troubleshooting
Occurrence of trouble
Check of battery voltage (24 V)
Does any part of air conditioner
unit or control unit operate?
No
E-1 Air conditioner does not
operate
Repair
Inspection of troubled part
Repair
Inspection with troubleshooting
table
Repair
Inspection of troubled part
Repair
YES
Inspection with self-diagnosis
function
(* 1)
No
OK
Troubleshooting with
troubleshooting chart
No
OK
Troubleshooting with gauge
pressure
No
OK
End
* 1: See TESTING AND ADJUSTING
73-2
(6)
Air conditioner
TROUBLESHOOTING
BLOCK DIAGRAM AND CIRCUIT DIAGRAM OF CONTROL SYSTEM
BLOCK DIAGRAM AND CIRCUIT DIAGRAM OF CONTROL SYSTEM
6267
* 1. The internal air sensor, water temperature sensor, external air sensor, and AUTO SW AUTO LED are not
installed to the air conditioner having only the manual mode. The external air sensor is not installed to the
automatic air conditioner of PC78US-6, either.
Air conditioner
73-3
(6)
TROUBLESHOOTING
BLOCK DIAGRAM AND CIRCUIT DIAGRAM OF CONTROL SYSTEM
6268
73-4
(6)
Air conditioner
TROUBLESHOOTING
DETAIL OF AIR CONDITIONER UNIT
DETAIL OF AIR CONDITIONER UNIT
6269
* 1. The internal air sensor and external air sensor are not installed to the air conditioner having only the manual mode.
Air conditioner
73-5
(6)
TROUBLESHOOTING
ARRANGEMENT OF CONNECTOR PINS
ARRANGEMENT OF CONNECTOR PINS
* 1. The water temperature sensor, internal air sensor, sunlight sensor, and external air sensor are not
installed to the air conditioner having only the manual mode.
The external air sensor is not installed to the automatic air conditioner of PC78US-6, either.
a For the wiring harness connectors of M26, M84, and M85 on the air conditioner unit side, see Detail of air
conditioner unit
6270
6271
73-6
(6)
Air conditioner
TROUBLESHOOTING
ARRANGEMENT OF CONNECTORS AND HOW TO DISCONNECT
CONTROL UNIT CONNECTORS
ARRANGEMENT OF CONNECTORS AND HOW TO DISCONNECT
CONTROL UNIT CONNECTORS
a The following is the explanation for PC78US-6
and PC128/138US-2.
1. Arrangement of connector
1) Connectors M26, M84, and M85 are
installed under the rear part of the operator's
seat.
AJS01466
2) Connector M87 is in cover (1) under the right
rear part of the operator's cab.
a Connector M88 of the mode duct is described in
the text (See TESTING AND ADJUSTING,
Inspecting selection of air outlet (Mode door and
mode actuator)).
AJS01477
2. How to disconnect control unit connectors
1) Unhook claw (N) under left console bellows
(B) and remove plate (P).
2) Remove tray (T) and screw (S), and then lift
up cover (C) and control unit and disconnect
connectors M80 and M81.
9JS02170
Air conditioner
73-7
(6)
TROUBLESHOOTING
HOW TO INSPECT ELECTRIC PARTS
HOW TO INSPECT ELECTRIC PARTS
kWhen removing each electric part, turn the starting switch OFF.
a See Detail of air conditioner unit
a Even if the water temperature sensor, internal air
sensor, and thermostat are normal, if a clip is
removed by vibration and the sensor is separated from the object, the system does not work.
1. Water temperature sensor and internal air
sensor
* Not installed to the air conditioner having only
manual mode.
a Remove the air conditioner unit to inspect
these sensors.
• Measure the resistance between the terminals.
2.
6272
External air sensor
* Not installed to the air conditioner having only
manual mode.
Not installed to the automatic air conditioner
of PC78US-6, either.
a On PC128/138US-2, this sensor is installed to
the battery relay bracket.
• Measure the resistance between the terminals.
(The characteristics of this sensor are the
same as those of the internal air sensor.)
3. Sunlight sensor (1)
* Not installed to the air conditioner having only
manual mode
a Since the current is small (several 10 µA), it
cannot be checked with a circuit tester.
a On PC78US-6 and PC128/138US-2, this sensor is installed on the monitor panel.
6273
4. Thermostat
a The thermostat unit cannot be inspected in the
field (since 24V power source is necessary
and the ON/OFF range is 1.5 - 6 °C)
a Inspect the thermostat without removing it
from the machine (See E-2 Air is not cooled)
a Removal: Remove the air conditioner unit,
and then remove the thermostat
5. Pressure switch
(See STRUCTURE AND OPERATION, Outline
of main parts, 6.4)
73-8
(6)
9JS02205
Air conditioner
TROUBLESHOOTING
HOW TO INSPECT ELECTRIC PARTS
a Before performing the following work (6. - 10.),
remove the cover under the seat.
6. Resistor
(1) Remove connector [N] from the resistor.
(2) Measure the resistance between terminal L
and terminal Mo. Resistance between L and
Mo: 7.3 z
a The resistance has effects on the operation when the fan speed (air flow) is at the
minimum.
a Before performing the following work,
remove the cover under the seat.
7. Power transistor
(1) Disconnect connector [L] of the power transistor.
(2) Check the continuity between the terminals
on the power transistor.
a The power transistor has effects on the
lowest 3 levels of the fan speed (air flow)
control.
8. MAX HI relay
(1) Disconnect connector [M] from the MAX HI
relay.
(2) Check the continuity between the terminals
on the MAX HI relay side.
a This relay is turned ON when the fan
speed (air flow) is set to the maximum
(MAX HI).
6274
6275
6276
9. A/C (Air conditioner) relay
(1) Disconnect connector [H] from the air conditioner relay.
(2) Check the continuity between the terminals
on the air conditioner relay.
a Turn the compressor OFF.
10. OFF relay
(1) Disconnect connector [K] from the OFF relay.
(2) Check the continuity between the terminals
on the OFF relay side.
a This relay is used to turn the fan (all airflow) OFF.
Air conditioner
6277
73-9
(6)
TROUBLESHOOTING
TROUBLESHOOTING CHART
TROUBLESHOOTING CHART
The numbers in the boxes are the item Nos. in the troubleshooting table.
1. Cooling trouble
Cooling trouble
Check of spurting air
temperature
Air flow is insufficient or
air does not come out
Air flow is normal
Check of operation of blower
fan motor
1 Blower fan motor does not
revolve or its speed is different from set value
Both high pressure and low pressure are low
Check or revolution of
compressor
2 Blower fan motor is normal
but air flow is insufficient
3 Compressor operates
normally
Both high pressure and low pressure are high
High pressure is
high and low pressure is low
4 Compressor does not
revolve at all or its
speed is low
High pressure is
low and low pressure is high
2. Heating trouble
Heating trouble
Check of spurting air
temperature
Air flow is insufficient or
air does not come out
Air flow is normal but air
temperature is low
Check of operation of blower
fan motor
1 Blower fan motor does
not revolve or its speed
is different from set value
73-10
(6)
5 Blower fan motor is
normal but air flow is
insufficient
6 Check of hot
water
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING TABLE
TROUBLESHOOTING TABLE
1. Blower fan motor does not revolve or its speed is different from set value.
a See the troubleshooting for the electrical system "E-3 Air does not come out or air flow is abnormal"
Possible cause
Check method
Remedy
Defective OFF relay
See check of relay
Replace
Disconnection of wire or
defective connection
Check ground wire and connector of blower fan
motor for disconnection
Repair broken parts and
connect correctly
Defective blower motor
Check 2 lead wires of motor with circuit tester. If
there is not continuity, motor is defective
Replace
Resistor trouble
Check continuity with circuit tester (If there is not
Replace
continuity, resistor is defective)
Defective power transistor or
defective MAX HI relay
Move fan switches in order and check fan speed.
Replace
See section of check of relay
2. Blower fan motor is normal but air flow is insufficient.
Possible cause
Check method
Remedy
Air leakage
Check fitting condition of air conditioner unit case Replace
Obstacle on suction side of
evaporator
Check evaporator for stain and obstacle
Remove obstacle and clean
Defective amplifier of electronic thermostat or defective
contact of electronic thermostat sensor
Evaporator is frozen. Check sensor clip. Check
sensor for dirt
Repair or replace
3. Air flow is normal or compressor operates normally.
Possible cause
Check method
Excessive or insufficient
refrigerant
Insufficient refrigerant
Overcharge with refrigerant
Judgment by pressure at
inlet/outlet of compressor
Air conditioner
If HFC-134a is used as refrigerant, its quantity
cannot be checked through sight glass.
Accordingly, check by connecting gauge manifold.
Purpose of sight glass is to check refrigerant flow
Remedy
Collect refrigerant, then
charge with proper quantity of refrigerant again
Repair leaking part, then
charge with proper quantity of refrigerant again
Collect refrigerant, then
charge with proper quantity of refrigerant again
Normal pressure range
Low pressure: Approx. 0.13 - 0.2 MPa
{1.3 - 2.0 kg/cm2}
See Troubleshooting with
High pressure: Approx. 1.5 - 1.7 MPa
gauge pressure
{15 - 17 kg/cm2}
These values are for following condition, however.
Temperature in cab: 30 - 35 °C
Engine speed: Approx. 1500 r/min
73-11
(6)
TROUBLESHOOTING
TROUBLESHOOTING TABLE
4. Compressor does not revolve at all or its speed is low.
a
See "E-2 Air is not cooled"
Troubled part
Possible cause
Check method
Remedy
Belt
Loosened belt
Vibration amplitude of belt is large
Adjust tension
Compressor
Trouble in compressor
Slip of belt
Repair or replace
Low battery voltage
Slip of clutch
Charge battery
Layer short circuit in coil
Slip of clutch
Replace magnet clutch
Oil on clutch surface
Magnet clutch is dirty and slips
Clean clutch surface or
replace clutch
Measure clearance between clutch
plate and clutch wheel with feeler
gauge
Proper clearance: (0.3 - 0.6 mm)
Repair
Inspect with circuit tester
Replace
Magnet clutch Too large clearance between
drive plate and pulley
Disconnection of coil
Disconnection in wiring or
When clutch is turned ON, magnet
defective connection of ground does not attract. Check ground wire
wire
and connections
Repair
5. Blower fan motor is normal but air flow is insufficient.
Possible cause
Large duct resistance
Check method
Check duct for crushing and clogging
Remedy
Repair
duct joints for defective duct seal and disconAir leakage through duct joints Check
nection of duct
Repair
Clogging of heat core fins
Repair
Check heater core fins for clogging
6. Check of hot water
Possible cause
Check method
Remedy
Low engine coolant tempera- Warm up engine, and then check engine coolant tem- Find out cause
ture
perature
Low engine coolant level
Check coolant level in radiator
Add coolant
Insufficient circulation of
engine coolant
Check engine coolant piping for clogging (Hose, pipe, Bleed air and repair
and core)
7. Other items
Possible cause
Check method
Temperature cannot be
adjusted
See Troubleshooting for electrical system, E-4
Air outlet cannot be changed
See Troubleshooting for electrical system, E-5
Intake cannot be changed
See Troubleshooting for electrical system, E-6
73-12
(6)
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
Information in troubleshooting table
a The following information is summarized in the troubleshooting table and the related electrical circuit diagram.Before carrying out troubleshooting, understand that information fully.
Trouble
Phenomenon that appears on machine
Related information Information related to the detected trouble or troubleshooting
Cause
1
Standard value in normal state/Remarks on troubleshooting
<Contents of description>
• Standard value in normal state to judge possible
causes
• Remarks on judgment
<Troubles in wiring harness>
Possible causes of trouble • Disconnection
(Given numbers are referConnector is connected imperfectly or wiring harence numbers, which do
ness is disconnected
not indicate priority.
Possible causes and
Perform troubleshooting
<Precautions for troubleshooting>
standard value in noraccording to these num(1) Entry order of pin Nos. and handling of circuit
mal state
bers, however.)
tester leads
Connect positive (+) lead and negative (-) lead of
2
circuit tester as explained below for troubleshooting, unless otherwise specified
• Connect positive (+) lead to pin No. or wiring harness entered on front side
• Connect negative (-) lead to pin No. or wiring harness entered on rear side
(2) Example of troubleshooting by inspection of multiple items
3 - defective
a Normal in 1 but abnormal in 2
At this time "- defective" shown at left is applied
a Grounding fault, short circuit with power source, and short circuit are not described since they are common
to all items. After checking all of the shown possible causes, if you still cannot detect the cause, check for
the above troubles.
a If a wiring harness is burnt, replace it.
• Grounding fault
Wiring harness which is not connected to chassis ground circuit is in contact with chassis ground circuit.
• Short circuit with power source
Wiring harness which is not connected to power source (24V) circuit is in contact with power source (24V)
circuit.
• Short circuit
Independent wiring harnesses are in contact with each other abnormally.
Related circuit diagram
This is a circuit diagram of the part related to troubleshooting
• The circuit diagram shows the connector Nos. and pin Nos.
• See "Arrangement of connector pins" and "Arrangement of connectors and how to disconnect
control unit"
• The circuit diagram shows the size and colors of wires.
W: White, B: Black, R: Red, G: Green, Y: Yellow, L: Blue, V: Purple, P: Pink, O: Orange, Br: Brown,
Gr: Gray, Sb: Sky blue, Lg: Light green, Dg: Dark green, Ch: Dark brown
a When there are 2 colors
Example: WY: Yellow line on white background
a The number before the wire color indicates the wire size.
• N.C.: Normally closed (Normally turned ON)
a Sockets (of relays, resistors, power transistors, etc.) are omitted.
Air conditioner
73-13
(6)
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
E-1 Air conditioner does not operate
Trouble
The air conditioner does not operate
Phenomenon that
• The LED on the control panel does not light up
appears on
• The compressor and fan motor do not revolve, either
machine
Check that the fuse is not broken and the engine starts normally in advance
Related information The ground wire of the air conditioner is connected to the chassis ground inside the
chassis wiring harness together with other electric parts (relay, valve, etc.)
Cause
Standard value in normal state/Remarks on troubleshooting
1) Turn starting switch OFF
2) Disconnectground terminal of battery
3) Lift up left console cover and control unit as 1 unit
1 Defective ground wire 4) Disconnect connector M80
Between terminal 10 of connector M80 and chassis Resisground
tance
1) Turn starting switch OFF
2) Disconnect ground terminal of battery
3) Lift up left console cover and control unit as 1 unit
4) Disconnect connector M80
Defective wiring har- 5) Connect ground terminal of battery
2 ness or defective con- 6) Turn starting switch ON
trol unit
Between terminal 2 of connector M80 and chassis
Voltage
ground
Possible
3 Defective control unit
causes
and standard
Disconnection in wirvalue in
ing harness
4
normal
• Intermediate wiring
state
harness
Between terminal 11 of connector M80 and chassis
ground
Voltage
Max.1 z
24V
24V
a Normal in 1 and 2
a When abnormal in 1 or 2, find out which wiring harness is disconnected (Perform after 2)
1) Turn starting switch OFF
2) Disconnect connector M85 (without connecting connector M80)
Female terminal of connector M80 and female terContinuity Made
minal of M85 (See circuit diagram)
a When abnormal in 1 or 2, find out which wiring harness is disconnected (Perform after 2 or 4)
Disconnection in wir1) Turn starting switch OFF
ing harness
5
• Attached to air condi- 2) Disconnect connector M26 and M85 (without connecting connector M80)
tioner unit
Male terminal of connector M26 and male terminal
Continuity Made
of M85 (See circuit diagram)
a When (abnormal in 1 or 2) and normal in 4 and 5, perform following
directly
1) Turn starting switch OFF
Disconnection in wir- 2) Disconnect ground terminal of battery
ing harness
3) Disconnect connector M26
6
• Wiring harness on
Between female terminal of connector M26 and
Continuity Made
machine
chassis ground
Female terminal of connector M26 and fuse 25A
terminal (See circuit diagram)
73-14
(6)
Continuity
Made
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
Related circuit diagram
6278
Air conditioner
73-15
(6)
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
E-2 Air is not cooled
Trouble
Air is not cooled
Phenomenon that
appears on machine
The compressor does not operate
Related information
See TESTING AND ADJUSTING, Inspecting relay
(Remove the cover under the seat for troubleshooting)
Cause
1 Defective compressor
Standard value in normal state/Remarks on troubleshooting
1) Turn starting switch OFF
2) Disconnect compressor connector
3) Turn starting switch ON
4) Turn air conditioner switch ON
Between connector terminal (there is on 1 pin) and
chassis ground
Voltage
24V
1) Turn starting switch ON
2) Turn air conditioner switch ON/OFF
Defective
air
conditioner
2 relay
Air conditioner relay makes ON/OFF sound
a See TESTING AND ADJUSTING, Inspecting relay
pressure
3 Defective
switch
Possible
causes and
standard
value in normal state
1) Turn starting switch OFF
2) Disconnect connector I
Between terminals of connector I on air conditioner Continuity
Made
unit side
a While pressure switch operates normally, continuity is may not be made.
Accordingly, measure gauge pressure. For pressure range, see STRUCTURE AND OPERATION. For connecting method, see 42-11 "Connecting
service tool"
kWhen replacing pressure switch, collect refrigerant gas in advance
Defective control unit or
in inter4 disconnection
mediate wiring harness
(between M81 and M84)
1) Turn starting switch OFF
2) Disconnect connector M84
3) Turn starting switch ON
4) Turn air conditioner switch ON
Between female terminal of connector M84 and chasResistance Max. 1z
sis ground
1) Turn starting switch OFF
Disconnection in wiring 2) Lift up left console cover and control unit as 1 unit
3) Disconnect connectors M81 and M84
5 harness
• Intermediate wiring harFemale terminal of connector M81 and female terminess
nal of M84
6 Defective control unit
Continuity
a Abnormal in 4 and normal in 5
–
1) Turn starting switch OFF
Defective thermostat or 2) Disconnect connector I
wiring harness
3) Disconnect connector M84
7 (Air conditioner unit
Between 0.3GY on wiring harness side of connector and male pin
does not need to be
removed)
25 (0.3GW) of connector M84
Continuity
Set cooling level to maximum to freeze evaporator
(Set air flow to minimum)
8 Defective thermostat
Disconnection in wiring
9 harness
• Attached to air
conditioner unit
73-16
(6)
Made
Made
Turned
Compressor OFF before
freezing
a Protective circuit of thermostat turns operation OFF when temperature is 1.5
- 6°C. Accordingly, if protective circuit operates normally, compressor may
not revolve. Check again before judging thermostat defective
1) Turn starting switch OFF
2) Disconnect connectors M84, M85, M26, and I and air conditioner relay
Referring to circuit diagram, check continuity
Continuity
Made
a To check around thermostat, air conditioner unit must be removed and disassembled
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
Related circuit diagram
6279
9JS02181
Air conditioner
73-17
(6)
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
E-3 Air does not come out or air flow is abnormal
Trouble
Air does not come out or air flow is abnormal
Phenomenon that appears on • The fan motor does not operate
machine
• Air flow is different from the setting of the control panel
See TESTING AND ADJUSTING, Inspecting relay (Remove the cover under the seat for troubleshooting.) See How to inspect electric parts
Related information
Cause
1 Defective OFF relay
Standard value in normal state/Remarks on troubleshooting
1) Turn starting switch ON
2) Turn air conditioner switch ON/OFF. OFF relay makes ON/OFF sound
When air does not come
out at any of 4 levels
a See TESTING AND ADJUSTING, Inspecting relay
2 Defective fan motor
1) Turn starting switch OFF
2) Disconnect connector O
Between terminals of connector O on air conditioner unit side
–
Continuity
Made
1) Turn starting switch ON
2) Turn air conditioner switch ON
3) Set air flow to MAX HI and medium alternately
Defective
MAX
HI
relay
3
Air flow changes (MAX HI relay makes ON/OFF sound)
*1
a See TESTING AND ADJUSTING, Inspecting relay. If air flow cannot be set to maximum (relay is
kept turned OFF) or it is kept at maximum regardless of setting of air flow (relay is kept turned
ON), replace MAX HI relay
1) Turn starting switch ON
2) Turn air conditioner switch ON
Defective power transis- 3) Set air flow to lower 3 levels
4 tor
Air flow is increased as level is increase to 2 and 3
*1
a If air flow is kept at minimum (power transistor is kept turned OFF) or at level 3 (power transistor is kept turned ON) regardless of setting of air flow, replace power transistor
1) Turn starting switch ON
2) Turn air conditioner switch ON
3) Set air flow to minimum
5 Defective resister
Possible
causes and
standard value
in normal state
Air flows out a little (a If air does not flow out only when setting is at minimum, replace resistor)
1) Turn starting switch OFF
2) Disconnect connector N
Resistance
Approx.
7z
Between female terminal 23 of connector M84 and chassis ground
Resistance
Max.1z
1) Turn starting switch OFF
2) Disconnect connector M84
Defective control unit or 3) Turn starting switch ON
6 intermediate wiring har- 4) Turn air conditioner switch ON
ness (between M81 and 5) Set air flow to maximum
M84)
Between female terminal 31 of connector M84 and chassis ground
Resistance
Max.1z
Voltage
1 - 5V
Continuity
Made
Between resistor terminals MO and L (See 6. How to inspect electric parts)
1) Turn starting switch OFF
2) Disconnect connector M84
3) Turn starting switch ON
4) Turn air conditioner switch ON
1) Turn starting switch OFF
2) Disconnect connector M84
3) Turn starting switch ON
4) Turn air conditioner switch ON
5) Set air flow to intermediate level 2
Between female terminal 22 of connector M84 and chassis ground
1) Turn starting switch OFF
Disconnection in wiring 2) Lift up left console cover and control unit as 1 unit
harness
3) Disconnect connectors M81 and M84
7
• Intermediate wiring harFemale terminal of connector M81 and female terminal of connector
ness
M84 (See circuit diagram)
73-18
(6)
8 Defective control unit
a Abnormal in 6 and normal in 7
Disconnection in wiring
harness
9 • Attached to air conditioner unit
1) Turn starting switch OFF
2) Disconnect connectors M84 M26, L, N, and O, OFF relay, and MAX HI relay
Referring to circuit diagram, check continuity
–
Continuity
Made
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
* 1. When either of the MAX HI relay (kept turned ON) or power transistor (kept turned ON) is broken, it is diffi
cult to see which one is broken. In this case, check them according to the following procedure.
1) Turn the starting switch OFF and remove the MAX HI relay.
2) Turn the starting switch and air conditioner switch ON and set the air flow to lower 3 levels to see if the
air flow is normal (changed).
Normal o MAX HI relay is defective, Abnormal o Power transistor is defective
Related circuit diagram
6280
9JS02180
Air conditioner
73-19
(6)
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
E-4 Temperature cannot be adjusted
Trouble
Temperature cannot be adjusted
Phenomenon that appears
The mix door does not move. (Normal: Operates to 8 levels according to setting of temperature)
on machine
Related information
See TESTING AND ADJUSTING, Inspecting temperature adjustment (Air mix door and mix
actuator)
(In air conditioner unit: Remove the cover under the seat for troubleshooting.)
Cause
Defective link mechanism between mix
1 actuator and mix door
(Removal of rod (3),
etc.)
Standard value in normal state/Remarks on troubleshooting
As temperature setting is changed from left end to
right end, levers (1) and (2) operates in 3 levels.
(Since there are 2 doors, there are 2 levers and 2
rods.)
Repair
Same as above
Remove, disassemble, and
• Mix actuator tries to move (motor sounds and
repair
vibrates) but cannot move
1) Turn starting switch OFF
2) Disconnect connector D
Defective mix actuator Between terminals 19 and 20 and between 8 and 20 of
Max.approx.4
Resistance
• Potentiometer
mix actuator connector on air conditioner unit side
Kz
• Motor coil
Continuity
Made
Between terminals 27 and 35 of mix actuator
connector D on air conditioner unit side
Diode range
1) Turn starting switch OFF
2) Disconnect connector D
3) Turn starting switch ON
4) Turn air conditioner switch ON
Between terminals 20 and 19 of mix actuator connecVoltage
5V
Defective control unit tor D on wiring harness side (regardless of setting of
–
or wiring harness
temperature control switch)
• Potentiometer
- 21 to + 21V
Voltage
• Motor drive
Between terminals 27 and 35 of mix actuator connector D on wiring harness side (Change of setting of tem- a Several seconds after
switch setting is
perature control switch: Left end - Right end)
changed
a If abnormal in 4, perform 5 and 6 to see which of wiring harness andcontrol unit
is defective
1) Turn starting switch OFF
Disconnection in wir- 2) Disconnect connectors D, M84, and M85
Terminal of connector D on wiring harness side and
ing harness
Continuity
Made
male terminal of M84 (See circuit diagram)
• Attached to air
conditioner unit
Terminal of connector D on wiring harness side and
Continuity
Made
male terminal of M85 (See circuit diagram)
1) Turn starting switch OFF
2) Lift up left console cover and control unit as 1 unit
3) Disconnect connectors M81, M84, M80, and M85
Disconnection in wir- Female terminal of connector M81 and female termiContinuity
Made
nal of M84 (See circuit diagram)
ing harness
• Intermediate wiring Female terminal of connector M80 and female termiContinuity
Made
harness
nal of M85 (See circuit diagram)
a If M85 (or M80) is disconnected, power is not supplied to control unit. Accordingly, M85 and M80 cannot be inspected by checking voltage similarly to 4.
Inspect them by checking continuity
–
Defective control unit a Abnormal in 4 and normal in 5 and 6
2 Locked air mix door
3
Possible
causes and
4
standard
value in
normal
state
5
6
7
73-20
(6)
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
Related circuit diagram
6281
9JS02169
Air conditioner
73-21
(6)
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
E-5 Air outlet cannot be changed
Trouble
The air outlet cannot be changed
Phenomenon that
appears on machine
Mode door (4) does not move
Related information
See TESTING AND ADJUSTING, Inspecting selection of air outlet (Mode door and mode actuator). (Carry out troubleshooting for mode duct (5).)
Cause
Defective mode
1 actuator
• Motor coil
2
Locked mode door
(4)
Standard value in normal state/Remarks on troubleshooting
1) Turn starting switch OFF
2) Disconnect connector M88
Made
Terminals 28 and 36 of mode actuator connector M88 on Continuity
mode duct side
a Diode range
a Since direction troubleshooting for mode door position sensor is impossible, carry
out troubleshooting indirectly by 3 and 4
Mode actuator tries to move (motor sounds and Mode door Revolution
(Visual
vibrates) but cannot move
check)
1) Turn starting switch OFF
2) Disconnect connector M88
3) Turn starting switch ON
4) Turn air conditioner switch ON
- 21 to + 21V
Voltage
Between terminals 28 and 36 of mode actuator connector M88 on wiring harness side (Change of setting of a Several seconds after
switch setting is
mode switch: Left end - Right end)
changed
5) Mode switch position: Left (Vent/Def)
Between terminals 4 and 20 of M88 on wiring harness
Voltage
0V
side
Possible
causes and
standard
value in normal state
Defective
control
unit or wiring harness
3
• Motor drive
• Mode door position
sensor
Between terminals 14-A (14-B) and 20 of M88 on wiring
harness side
Voltage
0V
Between terminals 5-A (5-B) and 20 of M88 on wiring
harness side
Voltage
5V
Between terminals 4 and 20 of M88 on wiring harness
side
Voltage
5V
Between terminals 14-A (14-B) and 20 of M88 on wiring
harness side
Voltage
0V
6) Mode switch position: Center (Bi-level)
Between terminals 5-A (5-B) and 20 of M88 on wiring
Voltage
0V
harness side
7) Mode switch position: Right (Foot)
Between terminals 4 and 20 of M88 on wiring harness Voltage
5V
side
Between terminals 14-A (14-B) and 20 of M88 on wiring Voltage
0V
harness side
Between terminals 5-A (5-B) and 20 of M88 on wiring Voltage
5V
harness side
a If abnormal in 3, perform 4 to see which of wiring harness and control unit is
defective (Keep M88 disconnected.)
1) Turn starting switch OFF
2) Lift up left console cover and control unit as 1 unit
3) Disconnect connectors M81 and M80
Female terminal of connector M81 and female terminal Continuity
Made
Disconnection in wir- of M88 (See circuit diagram)
harness
Female terminal of connector M89 and female terminal Continuity
4 ing
Made
of M88 (See circuit diagram)
(Inspect 3 pieces
together)
a If M85 (or M80) is disconnected, power is not supplied to control unit. Accordingly,
wiring between M85 and M80 (wiring on position sensor side) cannot be inspected
by checking voltage. Inspect it by checking continuity
a If abnormal in 4, perform 5 to see which wiring harness is defective. (Keep M80,
M81, and M88 disconnected.)
73-22
(6)
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
1) Turn starting switch OFF
2) Disconnect connectors M84, M85, and M87
Disconnection in wiring Female terminal of connector M81 and
Continuity
female terminal of M84 (See circuit diagram)
harness
Female terminal of connector M80 and
• Intermediate wiring
Continuity
female terminal of M85 (See circuit diagram)
harness
Possible
5
• Attached to air
Male terminal of connector M84 and female
causes and
Continuity
conditioner unit
terminal of M87 (See circuit diagram)
standard value
• Wiring harness on
Male terminal of connector M85 and female
in normal state
Continuity
machine
terminal of M87 (See circuit diagram)
Male terminal of connector M87 and female
Continuity
terminal of M88 (See circuit diagram)
6 Defective control unit a Abnormal in 3 and normal in 4
7 Defective mode duct
a Normal in 3
Move right console (2) inward, and then remove
covers (1) and (3).
a (4) is the mode door
a There is the mode actuator in mode duct (5).
a If duct joint A is moved, you can replace mode
duct (5).
Made
Made
Made
Made
Made
•
AJS01468
Related circuit diagram
6282
Air conditioner
73-23
(6)
TROUBLESHOOTING
•
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
Connector M87: Remove cover (1) at the right rear
of the operator's cab to find.
AJS01477
73-24
(6)
Air conditioner
TROUBLESHOOTING
TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)
E-6 Intake cannot be changed
Trouble
The intake cannot be changed
Phenomenon that The intake door does not move
appears on machine
Related information See TESTING AND ADJUSTING, Inspecting selection of intake
(Intake door and intake actuator) (Remove the intake duct for troubleshooting)
Cause
intake
1 Locked
door
Standard value in normal state/Remarks on troubleshooting
• Intake actuator tries to move (motor sounds and Intake door Revolution
(Visual
vibrates) but cannot move
check)
1) Turn starting switch OFF
2) Disconnect connector M83
3) Turn starting switch ON
4) Turn air conditioner switch ON
5) Press intake switch to select external/internal air
Defective intake
control
2 actuator,
unit, or wiring harness
Between terminals 32 and 24 of intake
actuator connector M83 on wiring
harness side
Voltage
±21V
a Reversal of polarity
(Several seconds after
switch setting is
changed)
1) Turn starting switch OFF
2) Lift up left console cover and control unit as 1 unit
Disconnection in 3) Disconnect connectors M81, M80, and M83
Possible causes and
harness
3 wiring
terminal of connector M81 and female
standard value in
• Intermediate wir- Female
Continuity
Made
terminal of M83 (See circuit diagram)
normal state
ing harness
Female terminal of connector M80 and female
Continuity
Made
terminal of M83 (See circuit diagram)
intake
4 Defective
a Normal in 2 and 3
actuator
a Abnormal in 2 and normal in 3, or perform following directly
1) Turn starting switch OFF
2) Lift up left console cover and control unit as 1 unit
3) Disconnect connectors M81 (Connect M80)
4) Turn starting switch ON
5) Turn air conditioner switch ON
5 Defective
control unit
6) Press intake switch to select external/internal air
Voltage
±21V
a Reversal of polarity
Between terminals 32 and 24 of
(Several seconds after
connector M81 on control unit side
switch setting is
changed)
Related circuit diagram
6283
Air conditioner
73-25
(6)
TROUBLESHOOTING
TROUBLESHOOTING WITH GAUGE PRESSURE
TROUBLESHOOTING WITH GAUGE PRESSURE
Connect the gauge manifold ( * 1) and carry out troubleshooting by reading the high and low gauge pressures of the cooling cycle.
a The gauge pressure varies largely with the
weather condition and operating condition of the
machine. Take care.
Indicated gauge pressure
<Pressure is normal>
Item
Atmospheric tempera ture
Engine speed
Air conditioner switch
Fan switch
Set temperature
Condition value
30 - 35 °C
1500rpm
ON
HI
Full cool
Cause
Check method
Air conditioner cycle is operating normally
If there is any trouble (cooling trouble), there is another 2cause
High pressure: Approx. 1.5 -1.7 MPa {15 -17 kg/cm } 2
Low pressure:
Approx. 0.13 - 0.2 MPa {1.3 - 2.0 kg/cm }
Insufficient refrigerant
Clogging of receiver drier
<Both high pressure
and low pressure are
low>
<Measurement condition for pressure>
Clogging of expansion valve
Refrigerant leakage through
tube of expansion
Low pressure becomes thermometer
valve (Blocking of valve
vacuum
passage)
Remedy
Collect refrigerant,
then charge with
proper quantity of
refrigerant again
Connect gauge manifold
(* 1)
(* 2)
There is temperature
difference between inlet and
outlet pipes of receiver drier Replace
Tank is frosty
(* 2)
Clean
or
replace
Expansion valve is frosty
(* 2)
Opening side of expansion
valve is not cold
(• Low gauge pressure
becomes vacuum)
Replace
(* 2)
Defective electronic
thermometer (thermometer
Adjust or replace
amplifier) or defective contact of Evaporator is frozen
sensor (removal of fixing clip)
Piping between receiver drier
and compressor is clogged or
Clogging or flattening of
flattened. If clogged comClean or replace
piping
pletely, low gauge pressure
becomes vacuum
(* 2)
Collect refrigerant,
then charge with
Overcharging with refrigerant
proper quantity of
Connect gauge manifold
refrigerant again
(* 1)
(* 2)
Clean,
repair
fins,
Stain of condenser, clogging repair or replace or
Defective cooling of condenser or crushing of fins, or defec- condenser
tive revolution of cooling fan
(* 2)
<Both high pressure and
low pressure are high> Defective adjustment of expan- Defective adjustment of
sion valve or defective installa- refrigerant flow rate
tion of thermometer tube (Valve Thermometer tube is not in Repair or replace
is opened too wide)
contact with evaporator pipe
(* 2)
Evacuate and then
charge with proper
Air in cycle
–
quantity of refrigerant again
(* 2)
or flattening of piping There is remarkable temper- Clean inside of cycle
<High pressure is high Clogging
compressor and con- ature difference between
or replace
and low pressure is low> between
denser
before and after clogged part
(* 2)
Defective
compressor
valve
or
Both
high
pressure
and
low
<High pressure is low
(Compression trouble of pressure are balanced while Replace
and low pressure is high> gasket
compressor)
compressor is in operation
(* 2)
* 1. See page 42-11 "Connecting service tool"
* 2. kWhen replacing a cooling cycle part, collect refrigerant, and then charge the air conditioner system with
refrigerant again. See page 52-14 "Procedure for collecting refrigerant gas" and page 42-32 "Charging with
refrigerant"
73-26
(6)
Air conditioner
DISASSEMBLY AND ASSEMBLY
63-12
(5)
DISASSEMBLY, ASSEMBLY OF CONTROL PANEL
Air conditioner