Model 34788
Recovery/Recycling/Recharging Unit
Shown: Model 34788
Rev C
Associated Models Include: Matco (H234788), MAC (AC34788), and Cornwell (RA-C34788) Branded Units.
34788 Service Manual
Disclaimer
The information contained in this manual was considered accurate at the time of printing.
Any corrections should be directed to:
SPX Corporation
6475 Technology Drive
Kalamazoo, MI 49009
Phone 269-544-5814
Fax 269-544-5832
This manual was made possible by the combined efforts of a number of individuals in the following departments: Technical Support, Engineering, Tech Pubs, and Marketing. I wish to express my gratitude to
everyone that contributed to this manual. — Scott Parde
© 2007, SPX Corporation.
All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval
system, or translated into any language in any form by any means without the written permission of SPX Corporation. Printed in the USA.
S.P. 09/2007 (Rev C)
2
34788 Service Manual
TABLE
OF
CONTENTS
Safety Warnings ................................................................................................... 4
General Information.............................................................................................. 5
Introduction ....................................................................................................................... 6
34788 Views ....................................................................................................................... 7
Operating Guidelines ....................................................................................................... 8
Unit Specifications ............................................................................................................ 11
Maintenance Schedule .................................................................................................... 12
Parts & Components............................................................................................ 15
34788 External Parts .........................................................................................................
34788 Internal Parts ..........................................................................................................
Component Assemblies ....................................................................................................
Plumbing Diagram & Parts List .......................................................................................
34788 Main Component Descriptions ..............................................................................
Alphabetical Parts List .....................................................................................................
16
18
20
27
28
30
Diagnostics .......................................................................................................... 37
Functional Check .............................................................................................................. 38
Service Center Menu Options .......................................................................................... 40
Output Step Test ................................................................................................................ 41
Depressurizing the Unit .................................................................................................... 42
12VDC Solenoid Test Procedure ...................................................................................... 43
Troubleshooting ................................................................................................................ 44
Service Instructions and Calibration ............................................................................... 54
System Wiring ................................................................................................................... 71
34788 Component Wiring ................................................................................................. 72
34788 Wiring Harnesses .................................................................................................... 75
Component Identification ............................................................................................... 86
Component Application Chart ......................................................................................... 87
Flow Diagrams .................................................................................................................. 88
Service Bulletins .................................................................................................. 97
Labor Rates .......................................................................................................... 103
Product Warranty ................................................................................................. 105
3
34788 Service Manual
SAFETY WARNINGS
It is extremely important to follow the instructions in this manual. DO NOT attach any hoses or accessories until
prompted by the unit. Improper setup
and failure of the unit will result.
Use only ROBINAIR Designated Replacement Components when servicing
your equipment. Refer to the operator’s
manual or this service manual for correct
replacement part number(s).
Always wear eye protection and protective clothing when working with refrigerants. Refrigerant can cause injury.
Read and follow all warnings in the
operator’s manual and this service
manual before operating the unit.
When replacing components, make certain the new parts are connected exactly
as your instruction sheet directs you to
do. If an instruction sheet was not included, connect the replacement part
just like the original. Mark or label wire
and plumbing disconnections so replacing the new parts will confirm the previous configuration.
Disconnect hoses and tubes with extreme caution as they may contain liquid refrigerant under pressure.
Always disconnect the unit from the
power source before making any repairs
or replacements to the components.
Risk of electrical shock!
Avoid the use of extension cords because the extension cord may overheat.
However, if you must use an extension
cord, the cord must be No. 14 AWG
minimum and should not exceed more
than 25 feet in length.
Always depressurize the machine before
servicing or replacing any components.
Pressurized tanks contain liquid refrigerant. Overfilling of the tank may cause
violent explosion and possible injury or
death. Do not recover refrigerants into
a non-refillable storage container. Federal regulations require refrigerants to be
transported only in containers meeting
DOT spec. 4BW or DOT spec. 4BA.
Be sure that the refrigerant level in the
tank does not exceed 80% of the tank
volume. Failure to monitor the level
could result in excessive hydrostatic
pressure, causing physical injury or
death.
If scale assembly and UL circuit are not
calibrated, scale can overfill the tank,
causing possible explosion and/or vehicle overcharge.
4
Warnings: Use this unit only with the
specified refrigerants. Cross-contamination with other refrigerant types will cause
severe damage to the A/C system and
to service tools and equipment. Do not
mix refrigerant types through a system
or in the same container!
Avoid breathing A/C refrigerant and lubricant vapor or mist. Exposure may irritate eyes, nose, and throat. When removing R-134a from the A/C system, use
service equipment certified to meet the
requirements of SAE J2210 (R-134a recycling equipment). If accidental system discharge occurs, ventilate work
area before resuming service. Make
sure there is adequate ventilation in the
vehicle servicing area.
Keep hands away from moving parts.
HFC-134a service equipment or vehicle
A/C systems should not be pressure
tested or leak tested with compressed
air. Some mixtures of air/HFC-134a
have been shown to be combustible at
elevated pressures. These mixtures are
potentially dangerous and may result in
fire or explosion causing injury or property damage.
Additional health and safety information
may be obtained from refrigerant and lubricant manufacturers.
34788 Service Manual
1
General Information
G E N E R A L I N F O R M AT I O N
Introduction .......................................................................................................... 6
Automatic Functions of the 34788 .................................................................................... 6
Additional Features of the 34788 ..................................................................................... 6
Optional Feature ............................................................................................................... 6
34788 Views .......................................................................................................... 7
Front View ......................................................................................................................... 7
Side View .......................................................................................................................... 7
Operating Guidelines ........................................................................................... 8
Using the Control Panel ................................................................................................... 8
Keypad Functions ............................................................................................................. 9
Menu Functions ................................................................................................................. 10
Unit Specifications ............................................................................................... 11
Maintenance Schedule ........................................................................................ 12
5
General Information
34788 Service Manual
Introduction
The Robinair 34788 recovers, recycles, evacuates, leak test, and recharges R-134a quickly and accurately. The
34788 recovers up to 20% more refrigerant and will recharge the vehicle to within ½ ounce of the charge capacity,
complying with the new SAE J-2788 standard. New ergonomic cabinet design provides additional storage areas
for tools, filters, and oil bottles, including a convenient fold-down control panel.
Automatic Functions of the 34788
√ Automatic Operation – Allows the technician to
program the unit to recover, recycle, evacuate, and
recharge without user intervention.
√ Vacuum Leak Test – Will monitor the vacuum level
after an evacuation and inform the technician of a
possible leak in the vehicle’s A/C system.
√ Automatic Refrigerant Refill – With this latest
advance, you never have to stop in the middle of
a job to change refrigerant tanks. The unit maintains a user selectable amount of refrigerant in an
internal vessel, and signals when it’s time to change
the supply tank, so no monitoring is required.
√ Automatic Air Purge – Eliminates damaging air
without any monitoring of gauges or opening of
valves.
√ The Automatic Oil Drain – The unit automatically
drains system oil captured during recover, and the
display reminds you to empty the bottle. Graduations on the container clearly show you how much
oil needs to be replaced.
√ Refrigerant Charging – Select a charge mode from
either the high side, low side, or both. Accuracy
features eliminate guesswork.
√ Refrigerant Management System – New and improved, system displays refrigerant use and monitors remaining filter life. Prompts appear when
1/3 of filter life remains.
√ Vacuum Function – Defaults to 15 minutes, but is
programmable up to 99 minutes. Remaining
vacuum time is displayed on the screen.
6
Additional Features of the 34788
• Control panel offers flat storage feature when not
in use.
• New 2X larger display makes the 34788 easier
than ever to use.
• Two large tool storage areas.
• Built-in storage for extra filter and compressor oils.
• Change between traditional & hybrid vehicle systems without fear of cross contamination with improved oil injection.
• Large Gauges that are easy to read.
• Heavy-duty compressor pulls from both high and
low sides during recovery.
Optional Feature
♦ Database Expansion Slot – Makes it easier and
faster to determine the charge capacity for refrigerant and oil. Included is the total system oil capacity as well as replacement oil amounts by component. The database (No. 34411) covers vehicles from 1994-2007.
34788 Unit
General Information
34788 Service Manual
34788 VIEWS
Control Panel
FRONT VIEW
Digital Display
and Keyboard
Shelves for tools
and accessories
Convenient
Built-in Handle
and Hose Storage
Oil Inject
Bottle
Oil Drain Bottle
Front
Panel
Database
Expansion Slot
Locking
Casters
Convenient Handle
for moving unit
Large Wheels
for mobility across
air lines, power
cords, grates
Low- and
High-Side Hose
Storage for Oil
Inject Bottles/
Filter Drier
Power Cord
Oil Drain
Bottle
Electronic Scale &
Calibration Device
Fill Hose
SIDE VIEW
7
General Information
34788 Service Manual
OPERATING GUIDELINES
Using the Control Panel
Function Keys
The function keys are used to start, stop, and select the
service functions. These keys and their function are
explained on the following page.
Low-Side Gauge
Shows the A/C system’s low-side pressure.
High-Side Gauge
Shows the A/C system’s high-side pressure.
Low-Side Selection Indicator
Illuminated blue light indicates low-side selection.
Arrow Keys
The UP and DOWN arrow keys are used for scrolling
through menu items.
High-Side Selection Indicator
Illuminated red light indicates high-side selection.
Digital Display
Visual interface between the operator and the machine.
Low-Side
Gauge
High-Side
Gauge
Numeric Keys
Used to input numerical values, change evacuation time,
vacuum levels, or recharge weight.
Database Key
Provides access to optional Vehicle/Refrigerant Database.
Low-Side Selection
Indicator
High-Side Selection
Indicator
Digital Display
Function Keys
Arrow Keys
Refrigerant Database
Key
Control Panel
8
Numeric Keys
General Information
34788 Service Manual
Keypad Functions
Start / Yes
Begins or resumes a function, or answers a query.
Stop / No
Terminates or pauses a function, or answers a query.
Menu
Displays the selection menu. (See Menu Functions on
following page.)
Arrows
The UP and DOWN arrow keys are used for scrolling
through menu items.
Refrigerant Database
Provides access to optional Vehicle/Refrigerant Database.
Automatic
Activates a menu which prompts the user through setting-up an automatic recover/vacuum/vacuum leak
check/charge sequence.
Recover
Activates the recovery sequence.
Vacuum
Activates the vacuum and automatic recycling sequence,
followed by an option to activate a vacuum leak check.
Inject Oil
Injects oil into the vehicle A/C system.
Charge
Charges the vehicle A/C system with a programmed
amount of refrigerant.
Start / Yes
Stop / No
START/
YES
STOP/
NO
Menu
AUTOMATIC
1
Arrows
Automatic
MENU
Refrigerant
Database
2
3
ABC
DEF
4
5
6
GHI
JKL
MNO
7
8
9
PQRS
TUV
WXYZ
0
Recover
RECOVER
VACUUM
Vacuum
INJECT OIL
Inject Oil
CHARGE
SPACE
Refrigerant Database
Charge
Keypad
9
General Information
34788 Service Manual
Menu Functions
1. Press the MENU button on the keypad.
2. Press the UP or DOWN arrow key to scroll
through the menu choices shown on the second
line of the display:
SELECT LANGUAGE
SERVICE MENU
CALIBRATION CHECK
ADJUST TANK FILL LVL
MANUAL REFILL
REFRIG MANAGEMENT
MAINTAIN FILTER
MAINTAIN VACUUM OIL
SELECT UNITS
VERSION X.XX
Menu Choice: Select Language
Operator may choose to have prompts displayed in one
of three languages: English, Spanish, or French.
Menu Choice: Service Menu
For Robinair service center use only. (See section 3.)
Menu Choice: Calibration Check
Use to verify internal scale calibration.
Menu Choice: Adjust Tank Fill Lvl
When connected to a refrigerant source, the unit maintains a pre-set amount of refrigerant in the internal storage vessel (default is 15 lbs.). This value may be adjusted up/down to suite the user’s needs.
Menu Choice: Manual Refill
Use to transfer refrigerant from the source tank to the
internal storage vessel (ISV).
Menu Choice: Refrig Management
Displays the amount of refrigerant recovered, charged,
and replenished (for the life of the unit), and filtered (since
the last filter change).
10
3. Press START / YES to make a choice from the
menu. Press STOP / NO to pause during any
process, and STOP / NO a second time to exit a
process.
Start / Yes
Button
Stop / No
Button
Arrow Keys
Menu
Button
Menu Choice: Maintain Filter
The filter-drier removes acid, particulates, and moisture
from the refrigerant. To meet the requirements of UL
J-2788, it is mandatory to replace the filter-drier after
150 lbs. (68 kg) of refrigerant has been filtered. The
menu item will show how much refrigerant has been filtered since the last filter change, and allows the user to
reset the value once a filter change is complete. It will
be necessary to enter a 10-digit code, which appears
on the filter, to ensure compliance with UL J-2788.
Menu Choice: Maintain Vacuum Oil
For maximum vacuum pump performance, change
vacuum pump oil after every 10 hours of operation. This
menu item displays how long the vacuum pump has operated since the last oil change, and allows the user to
reset the value once an oil change is complete.
Menu Choice: Select Units
Operator may choose to have test results displayed in
Imperial (lbs.), Imperial (lbs. and oz.), or Metric (kg.).
Menu Choice: Version X.XX
Displays the revision level of the software in the unit.
General Information
34788 Service Manual
UNIT SPECIFICATIONS
34788 Unit - General Information
Volts:
115V *
Frequency:
60 Hz
Amps:
12.0A
R-134a 98 Class III, ARI 98 Class IV
High - 377 psig
Low - 171 psig
0 to 140°F (-18 to 60°C)
Refrigerants:
Design Pressure:
Storage Temperature Range:
50 to 120°F (11 to 49°C)
Operating Temperature Range:
43 cu. In spin-on type
Recycling Filter-Drier:
Unit Height:
49 in. (124.5 cm)
Unit Width:
34 in. (86.4 cm)
Unit Depth:
23 in. (58.4 cm)
235 lbs. (106.6 kg)
UL Listed
SAE-J2788
Shipping Weight:
Certified:
Hermetic Compressor (Cubigel)
Volts:
115V *
Frequency:
60 Hz
8.4A
Running Amps:
30.0A
Locked Rotor Amps:
.55 CU IN
Displacement:
5821
Capacity (BTU/HR):
13.5 oz/11.8 oz (400 cc/350 cc)
Oil Charge Capacity (Initial/Recharge):
ISO 22
POE Oil Type:
Vacuum Pump
Volts:
110V *
Frequency:
60 Hz
Running Amps:
Locked Rotor Amps:
4.5A
Contact Tech Support
Motor:
1/3 HP
Stages:
2
Flow Rate:
3 cfm (71 l/m)
Oil Capacity:
7.4 oz. (219ml)
* The voltage at the unit must be ±10% of the unit's rated voltage. Extension cords must
be a minimum of 14 AWG and kept as short as possible. (25 ft./7.6 m. or less)
11
General Information
34788 Service Manual
MAINTENANCE SCHEDULE
Test Required
Change vacuum pump oil.
Recommended Frequency
Every 10 hours of operation.
Change the Filter/Drier.
After recovering 150 lbs. (68 kg) of refrigerant
or after recovering refrigerant from a burnedout system.
Fiter/Drier Warning
After recovering 100 lbs. (45 kg) of refrigerant.
Check Scale (Refer to scale calibration instructions in
Diagnostic Section if needed.)
Monthly
Check for Leaks.
Monthly
Clean (vacuum) condenser panel.
Monthly
Clean cabinet and control panel.
Monthly
Check casters and wheels for proper operation. Lubricate
bearings and brake components if necessary.
Monthly
Inspect hoses and power cord for cuts and abrasions.
Daily
Due to normal wear and tear, the 34788 requires regular maintenance to guarantee safe operation and
optimum performance. The above chart provides a schedule of the recommended maintenance tasks.
12
34788 Service Manual
General Information
NOTES
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13
General Information
14
34788 Service Manual
P a r ts & C o m p o n e n ts
34788 Service Manual
2
PARTS & COMPONENTS
34788 External Parts ............................................................................................ 16
34788 Internal Parts.............................................................................................. 18
Component Assemblies ....................................................................................... 20
34788 Head Assembly .......................................................................................................
34788 Head Assembly-Exploded View ............................................................................
Station Pump Assembly, 115V ..........................................................................................
Compressor Assembly, 115V .............................................................................................
34788 Manifold Assembly .................................................................................................
Internal Tank Assembly ....................................................................................................
20
21
22
23
24
26
Plumbing Diagram and Parts List ....................................................................... 27
34788 Main Component Descriptions ................................................................ 28
Alphabetical Parts List ......................................................................................... 30
Disclosure:
Although most parts are listed, some part numbers are part of an
assembly available only to manufacturing.
Information and part numbers contained in this publication were
accurate at the time it was written. Any discrepancies should be
brought to the attention of Robinair Technical Support.
15
P a r ts & C o m p o n e n ts
34788 Service Manual
34788 EXTERNAL PARTS
5
11
1
6
7
2
9
10
3
12
8
3
4
34788 EXTERNAL PARTS
No.
1
2
3
4
5
6
7
8
9
10
11
12
16
Description
DECAL, FRONT, 34788
ENCLOSURE, HEAD-SHOULDER
FRONT PANEL
BASE ASSEMBLY
HEAD ASSEMBLY
POWER SWITCH
SIDE SUPPORT ASSEMBLY
OIL DRAIN BOTTLE
HIGH SIDE HOSE SPUD
LOW SIDE HOSE SPUD
DECAL, 1-800 PHONE NUMBER
REAR DOOR
Qty. Part No.
1
1
1
122293
1
122206
1
1 RA19343
9
539750
1
17756
1
1
1
1
121575
P a r ts & C o m p o n e n ts
34788 Service Manual
1
3
4
5
2
6
34788 EXTERNAL PARTS
No.
1
2
3
4
5
6
Description
OPERATOR'S MANUAL
WHEEL, PNEUMATIC, 10"
OIL INJECT BOTTLE
REAR DOOR
DOOR LATCH KIT
CASTER, 5" DIA X 2" WIDE
Qty. Part No.
1
539602
2
19823
1
19867
1
121575
2 RA19632
2 RA19631
17
P a r ts & C o m p o n e n ts
34788 Service Manual
34788 INTERNAL PARTS
SEE DETAIL C
34788 UNIT COMPONENTS
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Description
BASE ASSY
ASSY, SIDE SUPPORT
CENTER DIVIDER
SHELF, VACUUM PUMP
SCALE ASSEMBLY & MAGNET
GROMMET, COMPRESSOR
COMPRESSOR, ASSEMBLY, 115V
MANIFOLD, ASSEMBLY,
ENCLOSURE, HEAD-SHOULDER
PCB ASSEMBLY, RELAY BRD
BRACKET, PUMP MOUNTING
STATION PUMP, 115V, 3CFM
ISV ASSEMBLY
BOLT, 1/4-20 X 1/2"
FAN ASSEMBLY, 115V
SCREW, 10-24 X 5.8"
Qty.
1
1
1
1
1
4
1
1
1
1
2
1
1
2
1
2
34788 UNIT COMPONENTS
Part No.
122206
539750
RA20002
RA20020
RA20018
RA20013
RA20017
RA17416
No.
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Description
SLEEVE, COMPRESSOR
WASHER, 1/4" ID FENDER
BOLT, 1/4-20 X 2" SERR HEAR
LOCKNUT, 1/4-20
STABILIZER BRACKET
BOLT, 1/4-20 X 1.5"
BOTTLE, OIL DRAIN
PANEL, CONDENSER COVER
NUT, 8-32 SEMS
BRACKET, POWER CORD
BUSHING, HEYCO
BRACKET, CAPACITOR
CAPACITOR, 115V COMP.
CAP, 38MM METAL DRILLED
NUT, NYLON
FITTING, STRAIGHT THRU
NOTE: The above parts listing may refer to parts located on unit diagrams on following page.
18
Qty. Part No.
1
12
4
10
1
1
1
17756
1
6
4
1
1
1
1
1
1
P a r ts & C o m p o n e n ts
34788 Service Manual
SEE DETAIL A
DETAIL B
SEE DETAIL B
DETAIL A
34788 UNIT COMPONENTS
No.
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Description
BOTTLE, OIL INJECT
CIRCUIT BREAKER, 15 AMP
SCREW, 1/4"-20 X 3.4"
SCREW, 8-32 X 3/8 SEMS
"O" RING
RUBBER BUMPER
WASHER, 1/4" FLAT
SCREW, 1/4 X 3/4" PLASTITE
FRONT PANEL ASSEMBLY
DOOR, REAR
MAGNET (PART OF SCALE ASSY)
SCREW, 1/4 -20 X 3.5 LONG
SCREW, 1/4-20 X 1/2" LONG
SWITCH, DPST (I/O)
SCREW, 6-32 X 3/8
DOOR LATCH KIT
Qty.
1
1
13
1
1
1
7
18
1
1
1
1
1
1
5
2
Part No.
19867
518638
DETAIL C
122293
121575
RA20002
RA19343
RA19631
34788 UNIT COMPONENTS
No.
51
52
54
55
Description
Qty. Part No.
1
HEAD ASSEMBLY, 34788
ENCLOSURE, HEAD-HINGE COVER 2
1 RA20014
POWER SUPPLY, 12 VOLT
SCREW, SOCKET HD CAP M3-.5 X 5 4
NOTE: The above parts listing may refer to parts located on unit diagrams on previous page.
19
P a r ts & C o m p o n e n ts
34788 Service Manual
COMPONENT ASSEMBLIES
34788 HEAD ASSEMBLY
34788 HEAD ASSEMBLY
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
22
23
24
25
20
Description
Qty
ENCLOSURE, SWIVEL TOP-FRONT
1
DECAL, FRONT, 34788
1
SCREW, MACH 6-32 X .188
6
GAUGE, LOW SIDE
1
GAUGE, HIGH SIDE
1
ELBOW, 1/8 MP X 1/8 PNEUMATIC
2
NUT, 10-32 HEX SEMS
4
ENCLOSURE, SWIVEL TOP-BACK
1
ENCLOSURE, SWIVEL TOP-POCKET
1
PCB ASS'Y, SD CARD, NGEN RRR
1
ENCLOSURE, SWIVEL TOP-SD COVER 1
SCREW, THD FORM, 4-20,.50, PHD, PH 4
SCREW, #6-19 X 1/2 EH TORX PLAST
6
BEZEL
1
KEYPAD
1
PCB ASS'Y, DISPLAY/CONTROL BRD
1
SCREW, 6-32 X 3/8
4
CABLE, INTERCONNECT
1
CABLE, SD BOARD
1
TUBE, 1/8" RED
4'
TUBE, 1/8" BLUE
4'
Part No.
539955
539956
RA20011
RA20001
RA20001
RA20012
539995
539996
RA20003
RA20004
P a r ts & C o m p o n e n ts
34788 Service Manual
34788 HEAD ASSEMBLY
EXPLODED VIEW
23
22
Wiring Detail
21
P a r ts & C o m p o n e n ts
34788 Service Manual
STATION PUMP ASSEMBLY, 115V
RA20017
3
4
2
1
5
6
7
8
STATION PUMP ASSEMBLY, 115V
No.
1
2
3
4
5
6
7
8
Description
STATION PUMP ASSEMBLY
RESERVOIR ASSEMBLY
BRASE DISCHARGE FITTING *
BRASS INLET FITTING *
SIGHT GLASS NUT *
OIL FILL PLUG *
SIGHT GLASS ASSEMBLY W/O-RING *
OIL DRAIN ASSEMBLY W/CAP *
Qty
1
1
1
1
1
1
1
1
Part No.
RA20017
RA19950
* Items followed by an asterisk are part of the Reservoir Assembly Kit
(RA19950) and are not sold separately.
22
P a r ts & C o m p o n e n ts
34788 Service Manual
COMPRESSOR ASSEMBLY, 115V
RA20020
1
DISCHARGE
SUCTION
SUCTION
SUCTION
SUCTION
DISCHARGE
COMPRESSOR ASSEMBLY, 115V
No.
1
Description
COMPRESSOR, 115V
RELAY
PROTECTOR
CAPACITOR
COVER
BAIL
BRACKETS
SCREW
SLEEVE
GROMMET
CAPACITOR WIRE
Qty
1
1
1
1
1
1
1
1
4
4
2
Part No.
RA20020
INC
INC
INC
INC
INC
INC
INC
INC
INC
INC
23
P a r ts & C o m p o n e n ts
34788 Service Manual
34788 MANIFOLD ASSEMBLY
RA20018
See Note
Next Page
B
32 5 X
2X
E
See Note
Next Page
SERVICE
PORT
A
See Note Next Page
C
See Note Next Page
D
34788 MANIFOLD ASSEMBLY
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Description
Qty. Part No.
MANIFOLD BLOCK, TOP
1
MANIFOLD BLOCK, LOWER
1
ELBOW, 1/8 MP X 3/8 PNEU COMP
3
HEAT EXCHANGER
1
O-RING
2
ACCUMULATOR SHELL
1
O-RING, PKR #SB17-119-7N
1
O-RING, PKR #SB17-143-7N
1
SEPARATOR ELEMENT
1
OIL SEPARATOR BOWL(1.5-3.0 IN LB 1
UNION, 1/8 MP X 1/8 MP X .97
2
TUBE, MANIFOLD CONN,(75 IN LBS) 1
FITTING, 1/4 MFL X 1/8 NPTF
1
SCHRADER CORE, (1.5-3.0 IN LBS)
1
CAP, 1/4 FLARE W/ O-RING
1
F
See Note
Next Page
See Note Next Page
34788 MANIFOLD ASSEMBLY
No.
16
17
18
19
20
21
22
23
24
25
26
27
29
30
31
32
Description
Qty.
SOLENOID, 12V DC DISCRETE
2
SOLENOID, 12V DC MAN,(75 IN LBS) 12
NUT, COMPRESSION (1/8 TUBE)
2
ELBOW, 1/8 NPTF X 1/4 COMP
1
ACCUM TRANSDUCER
2
CHECK VALVE, (75 IN LBS)
6
TEE, MALE BRANCH 1/8 NPTF
1
CHECK VALVE
1
FITTING, 1/8 NPT X 1/4 COMP
2
O-RING, C0873 2-240
1
FILTER DRIER, SPIN-ON
1
ELBOW, 1/8 MP X 1/8 PNEU
1
FITTING, HALF UNION .12MP X .25 FL 2
SWITCH, HIGH PRESSURE CUT-OUT 1
SCREW, SOCKET, (30 IN LBS)
1
BALL, MANIFOLD PLUG
5
NOTE: The above parts listing may refer to manifold parts on following page.
24
6X
Part No.
RA20009
RA20010
RA20008
RA20016
RA20015
34724
RA19427
P a r ts & C o m p o n e n ts
34788 Service Manual
3X
NOTE
A. Torque Schrader Core (item 14) to
1.5-3.0 IN. LBS.
B. Torque to 30 IN LBS ±5.
C. Apply Loctite 242 to threads of
Manifold Connection Tube (item
12) and torque to 75 IN. LBS.
D. Torque Manifold Solenoid (item 17)
to manifold with 75 IN. LBS. ±5.
Torque Fastener to 30 IN LBS ±5.
E. Press flush ±.030 with surface.
F. Torque Checkvalve (item 21) to 75
IN. LBS. (6 places)
G. Use (Loctite 565) on all pipe
threads.
H. Lubricate all O-rings on components before assembling.
NOTE: The above notes may refer to the manifold diagram on previous page.
25
P a r ts & C o m p o n e n ts
34788 Service Manual
INTERNAL TANK ASSEMBLY
3
4
9
5
10
8
11
2
7
12
6
13
1
Use Loctite 565 on all pipe threads.
Tank Tare Weight:
Worthington: 17.50 lbs. (7.94 kg.)
Air Com:
20.50 lbs. (9.30 kg.)
ISV ASSEMBLY
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
26
Description
ISV, INTERNAL
FITTING, STRAIGHT
SOLENOID, 12V DC DISCRETE
VALVE, BALL
VALVE, BALL
PRESSURE RELIEF, 450PSI
FITTING, TEE, .25FP X .25FP X .25MP
VALVE, BALL
TEMPERATURE PROBE
TRANSDUCER, AIR PURGE
TEE, MALE BRANCH 1/8 NPTF
ORIFICE, UNION .026
MUFFLER, AIR EXHAUST
Qty
1
1
1
1
1
1
1
1
1
1
1
1
1
Part No.
539477
210312
RA20009
539799
539798
RA19499
508690
540322
539472
539229
539654
539804
519605
P a r ts & C o m p o n e n ts
34788 Service Manual
PLUMBING DIAGRAM
USE LOCTITE 242 OR EQUIVALENT
ON THREADS
USE LOCTITE 242 OR EQUIVALENT
ON THREADS
STA-STRAP TUBES TO
SLOTS IN SIDE SUPPORT
USE LOCTITE 242 OR EQUIVALENT
ON THREADS
CUT END OF TUBE AT 45°
AND INSERT TO BOTTOM
OF BOTTLE
RED TUBE FROM
HIGH SIDE GAUGE
RED SERVICE HOSE
ROUTE THROUGH HOLES
IN SIDE SUPPORT
VACUUM PUMP EXHAUST
SHOULD PROTRUDE
APPROX. 1.5” INTO OIL
DRAIN BOTTLE
BLUE SERVICE HOSE
ROUTE THROUGH HOLES
IN SIDE SUPPORT
BLUE TUBE FROM
LOW SIDE GAUGE
USE LOCTITE 242
OR EQUIVALENT
ON THREADS
USE LOCTITE 242 OR EQUIVALENT
ON THREADS
BLACK TANK FILL HOSE
ROUTE THROUGH HOLE
IN SIDE SUPPORT
Plumbing Diagram Parts List
No.
1&2
Description
HOSE SET, SERV (HI & LOW-SIDE)
Qty.
Part No.
1
34722
3
TUBE, 1/4 OD X 0.040 ID
19"
120225
4
TUBE, 3/8" HIGH PRESSURE
16"
RA20005
5
HOSE, ISV LIQUID
1
541533
6
HOSE, VAPOR
1
539068
7
TUBE, 1/4 OD X 0.040 ID
23"
120225
8
HOSE, TANK FILL
1
539007
9
TUBE, 1/4 OD X 0.040 ID
28"
120225
10
TUBE, 3/8" HIGH PRESSURE
15"
RA20005
11
TUBE, COMPRESSOR TO MANIFOLD
1
538469
12
TUBE, 3/8" HIGH PRESSURE
12"
RA20005
13
TUBE, NYLON 1/8 OD X .070 ID
27"
121773
14
NUT, COMPRESSION (3/8 TUBE)
2
RA20006
15
O'RING (PKR #5-124) NEOPRENE
2
RA19916
16
NUT, COMPRESSION (1/4 TUBE)
1
RA20007
17
NUT, COMPRESSION (3/8 TUBE)
1
RA20006
18
STA-STRAP 8" LONE X .18"
2
Item # RA20005 (tube, 3/8”
high pressure) comes in a
length of 1.5’. Cut hose to
proper length as indicated in
plumbing parts list.
27
P a r ts & C o m p o n e n ts
34788 Service Manual
34788 MAIN COMPONENT DESCRIPTIONS
12V POWER SUPPLY — Provides 12 volts to power the
circuit boards, manifold block components, and the ISV
air purge solenoid.
BOTTLE, OIL DRAIN — Recovers the used oil during
the oil drain process.
BOTTLE, OIL INJECT — Stores oil for injection into the
A/C system.
BREAKER, 15 AMP — Protects the unit from drawing to
much current. If blown, unit is completely inoperative.
CALIBRATION BALL — Calibration standard that attaches to magnet under scale assembly. Used to verify
scale calibration.
CASTER — 5” x 2” wheels used for maneuvering unit.
CHECK VALVE — Allows flow in one direction only.
GAUGE, LOW SIDE — Monitors low-side pressure of
the vehicle being serviced.
HEAD ASSEMBLY — User interface panel for controlling
refrigerant recovery, recycling and recharging.
HIGH PRESSURE CUTOUT SWITCH — Switch opens
at 435 ± 10 psi (2999 ± 69 kPa) and resets at 320 ± 20 psi
(2066 ± 137 kPa). If pressure in the high side of the system
exceeds 435 psi (2999 kPa), the switch opens stopping all
functions.
INTERNAL STORAGE VESSEL (ISV) — Storage tank
that the recovered and recycled refrigerant is stored. Vapor, liquid, and air purge access is on-top of tank.
KEYPAD — Touch-pad cover for the front of the control
board.
COMPRESSOR — Moves refrigerant from the A/C system being serviced into the internal tank on the unit.
MANIFOLD BLOCK ASSEMBLY — Internal block assembly that contains solenoids, check valves and switches.
Refrigerant will flow through the manifold assembly for
proper distribution.
COMPRESSOR CAPACITOR — Used for starting the
compressor. Helps reduce the initial high current demand
required by the compressor on start-up.
MUFFLER, AIR EXHAUST — Disperses excessive air
from the ISV. Provides effective reduction of objectionable air exhaust noise.
COMPRESSOR OIL SEPARATOR — Removes the compressor oil from the refrigerant that is leaving the compressor. The stored oil is returned to the compressor when
the oil return solenoid receives power.
ORIFICE, UNION— Fitting used to reduce the flow rate.
POWER CORD — Supplies main power to the unit.
DISPLAY/CONTROL BOARD — Front display panel
and main control of the 34788.
PRESSURE RELIEF VALVE, 450 PSI — Spring loaded
safety valve use to releases pressure from internal tank
assembly if pressure exceeds 450 psi.
DOOR LATCH KIT — Used to replace spring-loaded
latch, retainer, and door latch receptacle.
RELAY BOARD — Relay control for all 12V and 115V
components.
FAN, 115V — Keeps the compressor’s electrical components cool.
SCALE ASSEMBLY — Measures the amount of refrigerant being charged and recovered.
FILTER DRIER, SPIN-ON — Used to remove moisture
and particles from refrigerant. Must be changed every
time 150 lbs of refrigerant is recovered.
SD CARD PCB ASSEMBLY — Used to read information
from Secure Digital (SD) memory cards.
SIGHTGLASS – Used to view vacuum pump oil level.
GAUGE, HIGH SIDE — Monitor high-side pressure of
the vehicle being serviced.
28
34788 Service Manual
SOLENOID (1), NORMAL DISCHARGE — When energized, allows refrigerant flow from the compressor to the
system oil separator, then to the internal storage vessel.
SOLENOID (2), HIGH-SIDE CLEAR — Energized during
the high-side clearing process.
SOLENOID (3), OIL INJECT — Energized during the Oil
Inject process to allow A/C system oil to be replenished.
SOLENOID (4), DEEP RECOVER — When energized,
uses vacuum pump to perform “deep” recovery of refrigerant from the system being serviced.
SOLENOID (5), HIGH-SIDE CHARGE — When energized, allows refrigerant from ISV to enter high-side of
system being serviced.
SOLENOID (6), LOW-SIDE CHARGE — When energized, allows refrigerant from ISV to enter low-side of system being serviced.
SOLENOID (7), HIGH-SIDE INLET — Allows an open
“pathway” for refrigerant flow and vacuum between the
A/C system high side and the 34788 unit. This solenoid is
powered during the Recover, Vacuum, and Leak Check
process.
SOLENOID (8), VACUUM — When energized, allows a
vacuum or deep recovery to be pulled on the A/C system
being serviced.
SOLENOID (9), LOW-SIDE INLET — Allows an open
“pathway” for refrigerant flow and vacuum between the
A/C system low side and the 34788 unit. This solenoid is
powered during the Recover, Vacuum and Flush process.
SOLENOID (10), RECOVERY — When energized, provides the primary pathway of removing refrigerant from
the system being serviced. This solenoid is also powered
during the Flush process.
SOLENOID (11), TANK FILL — When energized during
the Tank Fill process, allows refrigerant to flow from the
external supply tank to the ISV.
P a r ts & C o m p o n e n ts
SOLENOID (12), POWER CHARGE/FEEDBACK — Provides “feedback” pressure to assist the oil drain operation. Also, increases tank pressure to assist the charging
function.
SOLENOID (13), OIL RETURN — When energized, it
returns compressor oil from the compressor oil separator
to the compressor and equalizes the pressure on the high
and low side of the compressor.
SOLENOID (14), OIL DRAIN — Energized at the end of
the Recover process to drain oil.
SOLENOID (15), AIR PURGE — Energized to allow excessive air to be removed from the internal tank.
SWITCH ON/OFF — Allows the unit to be turned ON
and OFF.
SYSTEM OIL SEPARATOR — Heat exchanger with highside coils that provide internal heat to the canister causing saturated vapor and accumulated liquid refrigerants
to evaporate. This process prevents liquid refrigerant
from entering the compressor and separates the refrigerant oil.
TEMPERATURE PROBE — Monitors the temperature
inside the internal storage vessel (ISV).
TRANSDUCER, ACCUM (SYSTEM OIL SEPARATOR)
— Measures the pressure within the system oil separator.
TRANSDUCER, AIR PURGE — Measures the pressure
within the internal storage vessel (ISV).
TRANSDUCER, LOW-/HIGH-SIDE — Measures the
pressure of incoming refrigerant from the A/C system. Pressure readings are then relayed to the control board.
VACUUM PUMP — 115V pump designed to remove moisture and air from an A/C system. Also aids in the recovery
process by performing a deep recovery of A/C system.
WHEEL, PNEUMATIC 10” — Transport wheels.
29
P a r ts & C o m p o n e n ts
34788 Service Manual
ALPHABETICAL PARTS LIST
DESCRIPTION
PART #
12 VOLT, POWER SUPPLY
RA20014
34788 BASE, WHEELS & CASTORS ASSEMBLY
122206
34788 FRONT PANEL ASSEMBLY
122293
34788 REAR DOOR
121575
34788 SIDE SUPPORT ASSEMBLY
539750
AC POWER CORD
122770
AIR EXHAUST MUFFLER
519605
AIR PURGE TRANSDUCER
539229
BALL VALVE, AIR PURGE
539799
BALL VALVE, LIQUID
539798
BALL VALVE, VAPOR
540322
BOTTLE, OIL DRAIN
17756
BOTTLE, OIL INJECT
19867
CABLE, INTERCONNECT
539995
CABLE, SD BOARD
539996
CALIBRATION WEIGHT
540066
CAP AND FILLER TUBE
17191
CAP, OIL INJECT BOTTLE
RA19914
CAPACITOR, 110V START (COMPRESSOR)
RA19489
CASTER, 5” DIA X 2” WIDE
RA19631
CHECK VALVE KIT, MANIFOLD
RA20016
CHECK VALVE, VACUUM RELIEF
RA20015
CIRCUIT BREAKER, 15 AMP
518638
COMPRESSOR ASSEMBLY, 115 VOLTS
RA20020
30
NOTES
Kit inc. 6 valves
34788 Service Manual
DESCRIPTION
P a r ts & C o m p o n e n ts
PART #
NOTES
COMPRESSOR OIL, MSDS-POLYOL ESTER OIL
RA17283
COMPRESSOR START KIT
RA19489
CORE SCHRADER
RA19916
COUPLER SET, SERVICE (HIGH & LOW-SIDE COUPLERS)
18192
DISPLAY/CONTROL BOARD
RA20012
DOOR LATCH KIT
RA19632
DUST COVER, VINYL (OPTIONAL)
17488
FAN, 115V
RA17416
FILTER DRIER, SPIN-ON
34724
FITTING, STRAIGHT
210312
ISV Assembly
FITTING, TEE, .25FP X .25FP X .25MP
508690
ISV Assembly
GAUGE, HIGH SIDE
539956
GAUGE, LOW SIDE
539955
HARNESS, COMPRESSOR PIGTAIL
539991
HARNESS, FAN COMPRESSOR
539989
HARNESS, GROUND
539993
HARNESS, HIGH PRESSURE CUT-OUT
539992
HARNESS, MANIFOLD 1
539927
HARNESS, MANIFOLD 2
539987
HARNESS, POWER
539990
HARNESS, POWER SUPPLY
539994
HARNESS, TRANSDUCER
539988
HIGH PRESSURE CUT-OUT SWITCH
RA19427
HOSE SET, SERVICE (HIGH & LOW-SIDE HOSES)
34722
Optional
Less couplers
31
P a r ts & C o m p o n e n ts
DESCRIPTION
34788 Service Manual
PART #
HOSE, LIQUID
541533
HOSE, TANK FILL
539007
HOSE, VAPOR
539068
ISV TANK, INTERNAL
539477
KEYPAD & BEZEL ASSEMBLY
RA20001
MAGNET & SCALE ASSEMBLY
RA20002
MAINTENANCE KIT
13172
MANIFOLD ASSEMBLY
RA20018
MANUAL, OWNERS 34788
539602
MUFFLER, AIR EXHAUST
519605
NUT, COMPRESSION (1/4 TUBE)
RA20007
NUT, COMPRESSION (1/8 TUBE)
RA20008
NUT, COMPRESSION (3/8 TUBE)
RA20006
OIL DRAIN BOTTLE
17756
OIL INJECT BOTTLE
19867
OIL INJECT BOTTLE CAP
RA19914
OIL, VACUUM PUMP, CASE OF 12 PINTS
13119
OIL, VACUUM PUMP, CASE OF 12 QTS.
13203
OIL, VACUUM PUMP, CASE OF 4 GAL
13204
OIL, COMPRESSOR, MSDS-POLYOL ESTER OIL
RA17283
ORIFICE, UNION .026
539804
PCB ASSEMBLY, DISPLAY/CONTROL BOARD
RA20012
PCB ASSEMBLY, RELAY BOARD
RA20013
PCB ASSEMBLY, SD CARD
RA20011
32
NOTES
ISV Assembly
34788 Service Manual
DESCRIPTION
P a r ts & C o m p o n e n ts
PART #
NOTES
POWER SUPPLY, 12 VOLT
RA20014
PRESSURE RELIEF, 450 PSI
RA19499
PROTECTOR, 110V MOTOR OVERLOAD
RA19489
RELAY, 110V STARTING
RA19489
RELAY BOARD
RA20013
SCALE ASSEMBLY & MAGNET
RA20002
SD CARD, PCB ASSEMBLY
RA20011
SERVICE COUPLER LOW SIDE (R134A)
18190A
SERVICE COUPLER HIGH SIDE (R134A)
18191A
SERVICE COUPLER SET (HIGH & LOW-SIDE COUPLERS)
18192
SERVICE HOSE SET (HIGH & LOW-SIDE HOSES)
34722
SOLENOID, 12V DC DISCRETE
RA20009
SOLENOID, 12V DC MANIFOLD
RA20010
SWITCH, HIGH PRESSURE CUT-OUT
RA19427
SWITCH, ON-OFF, (I-O)
RA19343
TEE, MALE BRANCH 1/8 NPTF
539654
TEMPERATURE PROBE
539472
TRANSDUCER, AIR PURGE
539229
TUBE, 1/4 OD X 0.040 WALL
120225
Ordered by the foot
TUBE, 1/8" BLUE
RA20004
3 ft.
TUBE, 1/8" RED
RA20003
3 ft.
TUBE, 3/8" HIGH PRESSURE
RA20005
TUBE, COMPRESSOR TO MANIFOLD
538469
TUBE, NYLON 1/8 OD X .075ID
121773
Less couplers
ISV Assembly
Ordered by the foot
33
P a r ts & C o m p o n e n ts
DESCRIPTION
34788 Service Manual
PART #
VACUUM PUMP, 115V 3CFM
RA20017
VACUUM PUMP OIL, CASE OF 12 PINTS
13119
VACUUM PUMP OIL, CASE OF 12 QTS.
13203
VACUUM PUMP OIL, CASE OF 4 GAL
13204
VACUUM PUMP RESERVOIR ASSEMBLY
RA19950
WEIGHT, CALIBRATION
540066
WHEEL, CASTER, 5” DIA X 2” WIDE
RA19631
WHEEL, PNEUMATIC, 10”
19823
WIRE HARNESS, COMPRESSOR PIGTAIL
539991
WIRE HARNESS, FAN COMPRESSOR
539989
WIRE HARNESS, GROUND
539993
WIRE HARNESS, HIGH PRESSURE CUT-OUT
539992
WIRE HARNESS, MANIFOLD 1
539927
WIRE HARNESS, MANIFOLD 2
539987
WIRE HARNESS, POWER
539990
WIRE HARNESS, POWER SUPPLY
539994
WIRE HARNESS, TRANSDUCER
539988
34
NOTES
34788 Service Manual
P a r ts & C o m p o n e n ts
NOTES
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
35
P a r ts & C o m p o n e n ts
36
34788 Service Manual
34788 Service Manual
3
Diagnostics
DIAGNOSTICS
Functional Check ................................................................................................. 38
Service Center Menu Options ............................................................................. 40
Output Step Test ................................................................................................... 41
Depressurizing the Unit ....................................................................................... 42
12VDC Solenoid Test Procedure ........................................................................ 43
Troubleshooting ................................................................................................... 44
Unit Will Not Power-Up, No Display ................................................................................
Will Not Tank Fill ..............................................................................................................
Will Not Recover (First Stage) ..........................................................................................
Will Not Deep Recover (Second Stage) ..........................................................................
Will Not Perform Clearing ................................................................................................
Will Not Air Purge .............................................................................................................
Will Not Drain Oil ..............................................................................................................
Will Not Evacuate (Vacuum) .............................................................................................
Fails Leak Test ..................................................................................................................
Will Not Inject Oil ..............................................................................................................
Will Not Charge .................................................................................................................
Miscellaneous Error Messages .........................................................................................
44
45
46
47
48
49
49
50
51
51
52
53
Service Instructions and Calibration .................................................................. 54
Replacement Compressor (RA20020) Specifications & Service ....................................
Replacement Vacuum Pump (RA20017) Specifications & Service ...............................
Replacement High Pressure Cut-Out Switch (RA19427) .................................................
Replacement Scale Assembly/Magnet (RA20002) ..........................................................
Replacement Manifold Block (RA20018) .........................................................................
Replacement Manifold Solenoid (RA20010) ...................................................................
Replacement Display Board (RA20012) ...........................................................................
Replacement Relay Board (RA20013) ..............................................................................
Replacement Vacuum Relief Check Valve (RA20015) ....................................................
Replacement Manifold Check Valve (RA20016) ..............................................................
Replacement 3/8” High Pressure Tube (RA20005) ..........................................................
54
57
58
59
60
63
64
66
68
69
70
System Wiring ...................................................................................................... 71
34788 Component Wiring .................................................................................... 72
34788 Wiring Harnesses ...................................................................................... 75
Component Identification ................................................................................... 86
Component Application Chart ............................................................................. 87
Flow Diagrams ...................................................................................................... 88
37
Diagnostics
34788 Service Manual
FUNCTIONAL CHECK
Setup
1. Check to make sure all lines are correctly connected to tank and that all tank valves are open.
2. Connect the unit’s service hoses up to a test tank.
3. Plug unit into correct power source.
4. Turn main power on.
5. Unit will show “Version X.XXX” and “Relay
Version X.XXX.”
6. Unit will display “Refrig XX.XX lbs, Select Function.”
If low on refrigerant, unit may display “Low
Refrigerant” ”Fill Tank.”
7.
8.
9.
10.
Press the [Start] key so that No changes to Yes.
Once it says Yes, press the [Stop] key.
Unit will show “Display Acc Pressure.”
Press the [Stop] key again to exit.
Vacuum
1. Press the [Vacuum] key.
2. Unit will display “Checking Pressure.”
3. Program unit to pull a 2 ½ minute vacuum on the
test tank.
4. Press the [Start] key. You will be asked if you
want to do a leak test. Select “no” unless the complaint was for “unit fails leak test.”
5. Unit will display “Vacuum in Progress, Time Remaining XX.XX, Stop to Pause.”
6. Once the vacuum is complete, the unit will display
“Vacuum Complete, Any Key Exits.”
7. Press the [Stop] key.
8. Unit will display “Refrig XX.XX, Select Function.”
During the Vacuum process, you may hear the
unit purging air, this is normal operation.
Charging Test
34788 Keypad
Set unit up to Display Accumulator
Pressure
1. Press the [Menu] key.
2. Press the [Down Arrow] key two (2) times to
display “Service Menu.”
3. Enter the service code by pressing the following
keys individually: [2-2-0-0], and then press the
[Start] key.
4. From the Service Menu, press the [Down Arrow]
key until the display shows “Display Accumulator Pressure.”
5. Press the [Start] key.
6. Unit will display “Start Changes State, Display
Acc Pressure, No, Stop to Exit.”
38
1. Press the [Charge] key.
2. Unit will display “Charge XX.XX, Mode xxxx
Side, Charge Changes Mode, Arrow Key
Change Unit.”
3. Enter 02.55 lbs charge using the keypad.
4. Press the [Charge] key two (2) times so both the
red and blue lights are lit.
To verify Oil Inject function, you will need to
charge high-side only.
5. Press the [Start] key. “Charge in Progress”
appears on the display. (“Purging Air Please
Wait” may also show on display.)
6. “High and Low Side Charge in Progress Do
Not Disturb” will show on display. When the
unit gets towards the end of the charge, you will
notice that it slows down and then pulses the last
.10 lbs. in. This is done for charging accuracy.
34788 Service Manual
7. When charging is complete, the unit will display
“Charged XX.XX lbs, Press Start to Equalize
Hoses.”
8. Press the [Start] key.
9. Unit will display “Disconnect High Side
HoseCouple and Connect the Low Side Hose
and Start A/C Max, Start To Continue.”
10. Close both tank valves and press the [Start] key.
11. Unit will display “Equalizing Hoses Please
Wait.”
12. When hose equalizing is completed, unit will display “Disconnect LS Hose Start to Continue.”
13. Leave all hoses connected to test tank and make
sure that both tank valves are still closed.
14. Press the [Start] key.
15. Unit will display “Clearing Hoses Please Wait.”
16. When clearing is complete, unit will display
“Charge Complete X.XX lbs.”
17. Press the [Stop] key.
18. Unit will display “Refrig XX.XX lbs, Select Function.”
Recovery Test
1.
2.
3.
4.
Open both tank valves and invert test tank.
Press the [Recover] key.
Unit will display “Checking Pressure.”
Once the unit makes sure there is enough pressure, it will then display “Recovery Clearing.”
• Once the recovery clearing in done, the unit will
display the “Recovery in Progress, Recovered Amount X.XX, Accumulator Pressure
XX psi, Stop to Pause.”
• Accumulator pressure shows the amount of
pressure (refrigerant) that is being allowed in
during the recovery process. It should not exceed 38 psi. As the refrigerant is recovered
this number will decrease and eventually go into
a negative (inhg) number.
• Once the calibrated low side gauge reaches
“0”, the vacuum pump will start while the compressor is still running. The amount of vacuum
time depends on how long it took for the unit
to complete the recovery for the amount of refrigerant recovered.
Diagnostics
• Once the vacuum pump starts, you will notice
that the Accumulator pressure rises back to “0”
inhg*. This is accomplished by opening the oil
return and/or pressure feedback solenoid. The
reason for this is to keep the exhaust of the
vacuum pump out of a negative pressure situation so that oil is not pulled out of the vacuum
pump.
*During the Vacuum process the pressure will
float between 3 psi and 3 inhg.
5. When the vacuum pump timer times out, the unit
displays “Recovery in Progress, Recovered
X.XX lbs, Clearing Please Wait.”
6. When Clearing is complete, the unit will display
“Draining Oil, Accumulator Pressure XX,
Please Wait.” (Accumulator Pressure will rise to
16 psi.)
7. After the oil drain is complete, the unit will display “Recovery Complete, Recovered X.XX,
Check Oil Bottle.”
8. When the vacuum process is complete, turn off
the Display Accumulator Pressure.
To turn off the Display Accumulator
Pressure
1. Press the [Menu] key.
2. Press the [Down Arrow] key two (2) times to
display “Service Menu.”
3. Enter the service code by pressing the following
keys individually: [2-2-0-0], and then press the
[Start] key.
4. From the Service Menu, press the [Down Arrow]
key until the display shows “Display Accumulator Pressure.”
5. Press the [Start] key.
6. Unit will display “Start Changes State, Display
Acc Pressure, Yes, Stop to Exit.”
7. Press the [Start] key so that Yes changes to No.
8. Once it says No, press the [Stop] key.
9. Unit will show “Display Acc Pressure.”
10. Press the [Stop] key again to exit.
39
Diagnostics
34788 Service Manual
SERVICE CENTER MENU OPTIONS
These are the Service Options at the time of printing this service manual. Some options may be added
or deleted in future circuit board and software updates and revisions.
Never change the default settings unless directed from the factory. Otherwise the unit may fail
to operate properly.
Never give the programming or service codes to customers.
Service Menu
At the time of writing this manual, the software
version of the control board was 1.054 and the
relay board was 1.006. Software and functions
are subject to change without notice.
To access the Change Defaults menu, turn ON unit and
press the [MENU] button. Use the UP or DOWN arrow keys to scroll through the menu choices until “SERVICE MENU” is displayed.
Press [2-2-0-0] on the keypad, then press [START]
to enter Service Menu. Use the arrow keys to scroll
through the Service Menu choices. To reset the highlighted item, press [7-6-9-1] on the keypad, then press
[START].
Set UL — Follow the on-screen instructions to set the
UL circuit. For the Worthington ISV, you should have
43-lb. and 2-lb. weights to perform UL calibration;
for the Aircom ISV, you should have 45-lb. and 2-lb.
weights. Pot adjustment is not required on this unit.
Service Vacuum — This routine allows the service
center to have the machine pull a vacuum on the entire
circuit.
Service Leak Check — Unit is pressurized and tested
for leaks.
Output Step Test — Sends power to the item listed
on the display. (See Output Step Test on next page.)
Menu Choices
Keypad Test — Will run the operator through an process where every button on the keypad will be tested.
Maintenance Count — This routine allows a service
center to display and/or reset any of the service counters.
Board Test — Production use only.
Cal Tank Scale — Follow the on-screen instructions
to re-calibrate the scale.
Reset Board — This function will reset all board parameters and force re-calibration.
Production Tests — Production use only.
Display Pressure — Displays the low-side, ISV, and
accumulator pressures.
Air Purge Info — Displays the tank pressure, tank
temperature, and calculated tank PSI.
Prepare to Ship — Sets boot mode to first time customer power-on. When the unit is turned back on, the
user will have to set language, operating units, date &
time, clear unit, and perform an initial tank fill.
Set Tank Tare — Aircom ISV = 20.50 lbs (9.30 kg),
Worthington ISV = 17.50 lbs (7.94 kg.)
Display Acc Pressure — Allows the accumulator
pressure to be displayed on-screen.
40
Diagnostics
34788 Service Manual
OUTPUT STEP TEST
Refer to the 12VDC solenoid test procedure
on page-43 to check solenoid operation during the output tests.
The output test will turn on or turn off power
to the specified component. Do not perform
any test for an extended time period.
2. Press [2-2-0-0] on the keypad, then press
[START] to enter Service Menu.
3. Use the UP or DOWN arrow keys to scroll
through the menu choices until “OUTPUT TEST”
is displayed. Press [START/YES] to enter.
1. To access the Output Test, turn ON unit and press
the [MENU] button. Use the UP or DOWN arrow keys to scroll through the menu choices until
“SERVICE MENU” is displayed.
OUTPUTS – Use the UP or DOWN arrow keys
to select the component, then press the [START/
YES] button to toggle power ON or OFF.
OUTPUT STEP TEST
Component Order Energized Component
1
High-Side Inlet Solenoid
2
Low-Side Inlet Solenoid
3
High-Side Charge Solenoid
4
Low-Side Charge Solenoid
5
High-Side Inject Solenoid
6
Deep Recover Solenoid
7
Vacuum Solenoid
8
Recover Solenoid
9
Tank Fill Solenoid
10
Oil Drain Solenoid
11
Oil Return Solenoid
12
Power/Charge Solenoid
13
Normal Discharge Solenoid
14
HS Clear Solenoid
15
Air Purge Solenoid
16
Compressor
17
Vacuum Pump
18
Fan
41
Diagnostics
34788 Service Manual
DEPRESSURIZING THE UNIT
Always wear safety goggles when working with refrigerants. Contact with refrigerant can cause
eye injury. Disconnect lines and hoses with extreme caution! Pressurized refrigerant may be
present in lines and hoses. Always point lines and hoses away from you and anyone nearby.
Always unplug the station from the power source before removing any of the shrouding or
beginning any service work.
Unit is Functional
1. Perform Recovery function.
Unit is NOT Functional
2. Close Liquid valve on ISV.
1. Disconnect the high and low side service hoses
from vehicle. Make sure the coupler valves are
closed.
3. Turn unit off when oil drain error is displayed.
2. Disconnect the fill hose from the source tank.
4. The only refrigerant present may be in the vapor
hose between the ISV and manifold block.
3. Open the unit door and close the (3) ISV valves.
4. Connect an auxiliary recovery unit up to the manifold service port.
5. Start up the separate recovery unit and allow it to
pull the unit into a 13” vacuum.
6. When the unit is pulled down to this level, turn off
the auxiliary recovery unit, and disconnect from
the manifold service port.
7. Carefully disconnect or remove components as
there may be refrigerant present at these fittings.
42
Diagnostics
34788 Service Manual
12VDC SOLENOID TEST PROCEDURE
The solenoids that are used in the 34788 unit
cannot be tested using the P/N 17012 magnetic
solenoid tester.
The solenoids in this unit are activated from a 12VDC
power source and have a duty cycle of 25%. Duty Cycle
is the ratio of solenoid on-time to total cycle time. In this
particular scenario, the solenoid is on 25% (250μs) of the
total cycle and off for 75% (750μs) of the cycle.
When the solenoid is ‘first’ activated, it receives a 12VDC,
125ms pulse to energize (turn on) the solenoid coil. The
solenoid is then cycled on and off rapidly at a 50ms, 25%
duty cycle. Although the power to the solenoid is cycling
ON and OFF, the solenoid actually sustains the “ON”
state because the cycling process is happening so quickly,
the solenoid doesn’t have time to turn off until the power
is completely removed. Using this process to power the
solenoids requires less power and increases the
component’s life expectancy.
The best way to verify solenoid operation is to use an
oscilloscope. Viewing the solenoid’s duty cycle pattern
on the oscilloscope will provide the best information on
how the solenoid coil is performing. Set oscilloscope to
DC mode. Set the time to .2 ms/div and voltage range to
5 volts/div. Attach the scope probe to an energized solenoid. The pattern on the oscilloscope should look similar
to the sample below with amplitude of 12V. If the amplitude is not 12V, check the power supply. If the pattern
is irregular or doesn’t compare to the sample below, replace the solenoid coil.
If an oscilloscope is not available, a digital volt meter may
be used to check power applied to the solenoid. However, do NOT expect to see 12VDC on the DVM. Because most DVM’s use RMS to read voltages, the meter
will read an average voltage of 2.8 VDC due to the continuous 25% on, 75% off cycling of the solenoid.
An LED light may also be used to verify that a solenoid
is receiving power. Attach the leads of the 12VDC LED
light across the solenoid terminals. While watching the
LED, activate the solenoid from the service menu. The
LED should turn-on bright for a moment (initial 12VDC,
125ms activation pulse), then dim considerably when the
25% duty cycle begins.
1 Complete Cycle
Sustain Pulse, 25% Duty Cycle, 1kHz Cycle (low part of pattern is “On” time)
12V
750µs 75%
750µs
25%
250µs
125ms Activation Pulse (not to scale)
Off
250µs
On
25% Duty Cycle
43
Diagnostics
34788 Service Manual
TROUBLESHOOTING
Will Not Power-Up, No Display
1. Verify that unit is not plugged into an extension
cord. If it is, remove extension cord.
2. Verify AC power cord is properly connected to
a good AC power source at receptacle. Verify
that it is wired correctly and has a good ground.
3. Turn ON the main power switch. Verify that line
voltage is present at the input and output terminals of the switch.
• If line voltage is not present at power switch
input, check connections between power
switch and AC plug.
• If line voltage is present at power switch input,
but not at output with switch turned ON, replace power switch.
• If line voltage is present at both input and output of switch, proceed to next step.
4. Verify line voltage is present across pins 2 and 3
of connector J1 on the relay board.
• If line voltage is present, proceed to next step.
• If line voltage is not present, check connections between the power switch and connector J1.
5. If unit does not power up, check if the 15A circuit breaker (located on back of unit) has tripped.
15A Breaker Not Tripped
1. Switch off unit and unplug AC power cord from
receptacle.
2. Check the 15A breaker for continuity.
• If there is no continuity, replace circuit breaker.
• If there is continuity, plug the AC power cord
into the receptacle and switch unit on. Continue to next step.
44
3. Perform the following voltage checks:
• Verify line voltage is present across pins 3 and
4 of connector J3 on the relay board.
• If line voltage is not present, check for continuity between the 15A circuit breaker and J3
on the relay board. Repair as needed.
• If line voltage is present, replace the relay
board.
4. If all the proceeding steps fail to repair the problem, replace the display/control board.
15A Breaker Tripped
1. Switch off unit and reset circuit breaker. Switch
unit back on. If breaker trips after reset and AC
power has been tested good, the circuit breaker
needs to be replaced.
2. If breaker trips again after being replaced, switch
off unit and unplug all connectors on the relay board
except J1 (AC In) and J3 (Circuit Breaker).
Switch unit back on.
• If circuit breaker trips again, replace relay
board.
• If the circuit breaker doesn’t trip, turn off
power, plug-in one connector at a time, and
turn back on. Keep doing this until the circuit
breaker trips. Check all components associated with the last connector attached to the
relay board.
34788 Service Manual
Diagnostics
Will Not Tank Fill
Compressor Running:
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
10. Check the compressor for suction and discharge
performance.
11. Remove the filter and inspect all fittings and gaskets to verify that no obstructions exist. Replace/
repair gaskets as needed and reinstall filter.
12. Verify that the scale is unobstructed and calibrated.
3. Verify the tank hoses are properly connected and
threaded completely onto the ISV fittings.
4. Verify the ISV is not full or does not have excessive pressure. If excess pressure cannot be reduced with purging air, the refrigerant may be contaminated and should be handled appropriately.
5. Verify the fill hose is properly connected and
threaded completely onto the source tank fitting.
Check quick-seal on tank fill hose.
6. Verify that there is a minimum of 8 pounds (3.6
kilograms) of refrigerant in the source tank.
7. Verify the Tank Fill and Normal Discharge solenoids are receiving power and opening properly.
• If not receiving power, check the continuity of
the wiring between solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay board.
• Verify the solenoid coil is opening the solenoid
properly.
• Verify the operation of the Tank Fill check
valve—replace as needed.
The Tank Fill solenoid is controlled to maintain
35 psi in the accumulator.
8. Check the Power Charge, Recover, Oil Return, Oil
Drain, Deep Recover, and High-Side Clear solenoids for bleed-through—repair as needed.
Compressor does not run:
1. Check for proper power source, check circuit
breaker and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Verify that the ground wire between the
compressor’s electrical box and chassis ground is
securely fastened.
4. Check for 110 volts to the compressor.
• If there is no voltage to the compressor’s start
components, proceed to next step.
• If voltage is present at the compressor, jumper
the thermal overload. If the compressor runs,
check the compressor amp draw. If it is drawing locked rotor amps or not running, replace the
compressor. If the compressor is cool and
drawing low amperage, replace the thermal
overload.
5. Check for 110 volts from the relay board on connector J6, pins 3 and 4.
• If voltage is present, check wiring between the
relay board and the compressor’s start components. Repair as needed.
• If voltage is not present, replace the relay board.
• If after replacing the relay board, voltage is still
not present, replace the display/control board.
6. Perform functional check and recalibrate unit.
9. Check the Clearing Discharge check valve for
bleed-through—repair as needed.
45
Diagnostics
34788 Service Manual
Will Not Recover (First Stage)
Compressor running:
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
2. Verify the service hoses are properly attached to
the unit without any restrictions and coupler valves
are open.
3. Verify that ISV valves are open and tank hoses
are properly connected and threaded completely
onto the ISV fittings.
4. Verify the ISV is not full or does not have excessive pressure. If excess pressure cannot be reduced with purging air, the refrigerant may be contaminated and should be handled appropriately.
5. Verify that the Normal Discharge, Recover, HighSide Inlet and Low-Side Inlet solenoids are receiving power and opening properly.
• If not receiving power, check the continuity of
the wiring between solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
The Recover solenoid is controlled to maintain 35 psi max in the accumulator.
6. Check the High-Side Charge, Low-Side Charge,
Oil Inject, Oil Return, Vacuum, High-Side Clear,
Tank Fill, and Power Charge solenoids for bleedthrough and proper operation —repair as needed.
7. Check the compressor for suction and discharge
performance.
46
8. Remove the filter and inspect all fittings and gaskets to verify that no obstructions exist. Replace/
repair gaskets as needed and reinstall filter.
9. Verify that the accumulator transducer is functioning properly.
10. If all the proceeding steps fail to repair the problem, replace the display/control board.
Compressor does not run:
1. Check for proper power source, check circuit
breaker and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Verify that the ground wire between the
compressor’s electrical box and chassis ground
is securely fastened.
4. Check for 110 volts to the compressor.
• If there is no voltage to the compressor’s start
components, proceed to next step.
• If voltage is present at the compressor, jumper
the thermal overload. If the compressor runs,
check the compressor amp draw. If it is drawing locked rotor amps or not running, replace
the compressor. If the compressor is cool and
drawing low amperage, replace the thermal
overload.
5. Check for 110 volts from the relay board on connector J6, pins 3 and 4.
• If voltage is present, check wiring between the
relay board and the compressor’s start components. Repair as needed.
• If voltage is not present, replace the relay
board.
• If after replacing the relay board, voltage is still
not present, replace the display/control board.
Diagnostics
34788 Service Manual
Will Not Deep Recover (Second Stage)
Vacuum pump running:
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Verify the service hoses are properly attached to
the unit without any restrictions and coupler valves
are open.
8. Check the Clearing Discharge checkvalve for
bleed-through—repair as needed.
9. Check for suction at the intake of the pump. If
there is none, replace the pump.
10. Remove the filter and inspect all fittings and gaskets to verify that no obstructions exist. Replace/
repair gaskets as needed and reinstall filter.
11. Verify that the accumulator transducer is functioning properly.
4. Verify that ISV valves are open and tank hoses
are properly connected and threaded completely
onto the ISV fittings.
12. If all the proceeding steps fail to repair the problem, replace the display/control board.
5. Verify the ISV is not full or does not have excessive pressure. If excess pressure cannot be reduced with purging air, the refrigerant may be contaminated and should be handled appropriately.
Vacuum pump does not run:
1. Check for proper power source, check circuit
breaker and check electrical connectors for damage or corrosion.
6. Verify that the Normal Discharge, High-Side Inlet, Low-Side Inlet, Vacuum, Deep Recover, and
Power Charge (see note) solenoids are receiving
power and opening properly.
• If not receiving power, check the continuity of
the wiring between solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
2. If the unit is being run through an extension cord,
eliminate its use.
The Power Charge solenoid is controlled to
maintain 0 to 3 psi in the accumulator.
7. Check the High-Side Charge, Low-Side Charge,
Oil Inject, Oil Return, Recover, Tank Fill and
High-Side Clear solenoids for bleed-through and
proper operation—repair as needed.
3. Check for 110V at the vacuum pump connector,
pins 2 and 3.
• If voltage is present, replace vacuum pump
assembly.
• If voltage is not present, continue to next step.
4. Check for 110 volts from the relay board on connector J6, pins 1 and 2.
• If voltage is present, check wiring between the
relay board and the vacuum pump. Repair as
needed.
• If voltage is not present, replace the relay
board.
• If after replacing the relay board, voltage is still
not present, replace the display/control board.
5. Perform functional check and recalibrate unit.
47
Diagnostics
34788 Service Manual
Will Not Perform Clearing
Compressor Running:
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
9. Remove the filter and inspect all fittings and gaskets to verify that no obstructions exist. Replace/
repair gaskets as needed and reinstall filter.
10. If all the proceeding steps fail to repair the problem, replace the display/control board.
3. Verify the tank hoses are properly connected and
threaded completely onto the ISV fittings.
Compressor does not run:
1. Check for proper power source, check circuit
breaker and check electrical connectors for damage or corrosion.
4. Verify the ISV is not full or does not have excessive pressure. If excess pressure cannot be reduced with purging air, the refrigerant may be contaminated and should be handled appropriately.
2. If the unit is being run through an extension cord,
eliminate its use.
5. Verify the Normal Discharge, HS Clear, and Oil
Return solenoids are receiving power and opening properly.
• If not receiving power, check the continuity of
the wiring between solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
• Verify the operation of the Tank Fill check
valve—replace as needed.
6. Check the Power Charge, Recover, Oil Drain,
Deep Recover, and Tank Fill solenoids for bleedthrough—repair as needed.
7. Check the Normal Discharge check valve for
bleed-through—repair as needed.
8. Check the compressor for suction and discharge
performance.
3. Verify that the ground wire between the
compressor’s electrical box and chassis ground
is securely fastened.
4. Check for 110 volts to the compressor.
• If there is no voltage to the compressor’s start
components, proceed to next step.
• If voltage is present at the compressor, jumper
the thermal overload. If the compressor runs,
check the compressor amp draw. If it is drawing locked rotor amps or not running, replace
the compressor. If the compressor is cool and
drawing low amperage, replace the thermal
overload.
5. Check for 110 volts from the relay board on connector J6, pins 3 and 4.
• If voltage is present, check wiring between the
relay board and the compressor’s start components. Repair as needed.
• If voltage is not present, replace the relay
board.
• If after replacing the relay board, voltage is still
not present, replace the display/control board.
6. Perform functional check and recalibrate unit.
48
34788 Service Manual
Will Not Air Purge
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Check the 0.028” orifice between the ISV and
air purge solenoid for debris.
• If the orifice is contaminated or defective, repair or replace as needed.
• If the orifice is operational, proceed to the next
step.
4. Verify the Air Purge solenoid is receiving power
and opening properly.
• If not receiving power, check the continuity of
the wiring between solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
5. Verify that the tank temperature probe and pressure transducer are functioning properly.
Diagnostics
Will Not Drain Oil
For dye usage, please refer to Limited Warranty Statement.
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Verify the Oil Drain solenoid is receiving power
and opening properly.
• If not receiving power, check the continuity of
the wiring between solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
4. Verify that the accumulator transducer is functioning properly.
5. If the proceeding steps fail to repair the problem,
replace the display/control board.
6. If the proceeding steps fail to repair the problem,
replace the display/control board.
49
Diagnostics
34788 Service Manual
Will Not Evacuate (Vacuum)
Vacuum pump running:
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
9. Check plumbing between vacuum pump and service hoses for loose connections or fittings.
10. Replace vacuum pump.
2. If the unit is being run through an extension cord,
eliminate its use.
11. If all the proceeding steps fail to repair the problem, replace the display/control board.
3. Verify the service hoses are properly attached to
the unit (valves open) without any restrictions.
Vacuum pump does not run:
1. Check for proper power source, check circuit
breaker and check electrical connectors for damage or corrosion.
4. Be sure the two plastic vacuum lines are snug at
both ends and not obstructed. Check the pneumatic fittings for leaks.
5. Check for proper vacuum oil level in the vacuum
pump sight glass (oil level should be in the center
of the sight glass while the pump is running). Replace vacuum pump oil if necessary.
6. Check for suction at the intake of the pump. If
there is none, replace the pump.
7. Verify that the Vacuum, Low-Side Inlet and HighSide Inlet solenoids are receiving power and
opening properly.
• If not receiving power, check continuity of the
wiring between the solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
8. Check the High-Side Charge, Low-Side Charge,
Oil Inject, Recover, and Deep Recover solenoids
for bleed-through and proper operation—repair
as needed.
50
2. If the unit is being run through an extension cord,
eliminate its use.
3. Check for 110V at the vacuum pump connector,
pins 2 and 3.
• If voltage is present, replace vacuum pump
assembly.
• If voltage is not present, continue to next step.
4. Check for 110 volts from the relay board on connector J6, pins 1 and 2.
• If voltage is present, check wiring between the
relay board and the vacuum pump. Repair as
needed.
• If voltage is not present, replace the relay
board.
• If after replacing the relay board, voltage is still
not present, replace the display/control board.
5. Perform functional check and recalibrate unit.
Refer to vacuum pump service bulletin.
34788 Service Manual
Fails Leak Test
Diagnostics
Will Not Inject Oil
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Verify that the High-Side and Low Side Inlet solenoids are receiving power and opening properly.
• If not receiving power, check continuity of the
wiring between the solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
3. Verify the high-side service hose is properly attached to the unit without any restrictions and coupler valve is open.
4. Check the High-Side Charge, Low-Side Charge,
Oil Inject, Recover, and Vacuum solenoids for
bleed-through—repair as needed.
5. Verify that the low-side pressure transducer is
functioning properly.
6. If vacuum can not be maintained, use a refrigerant detector to check all plumbing hoses and fittings for leaks—repair as needed. Refer to the
Leak Test flow diagram illustrated in the Flow
Charts section.
7. If all the proceeding steps fail to repair the problem, replace the display/control board.
4. Verify a deep vacuum has been pulled on the system.
5. Verify the oil injector bottle is securely attached
and contains an appropriate amount of oil.
6. Verify the Oil Inject solenoid is receiving power
and opening properly when the Oil Inject Button
is pressed on the keyboard.
• If not receiving power, check the continuity of
the wiring between solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
7. Check the High-Side Inlet and High-Side Charge
solenoids for bleed-through—repair as needed.
8. If the proceeding steps fail to repair the problem,
replace the display/control board.
51
Diagnostics
34788 Service Manual
Will Not Charge
There is no component that "pumps" refrigerant into a system during the charge process.
The refrigerant flows in by a pressure transfer.
If the system is not in a vacuum, this unit will
not charge.
1. Check for proper power source, check circuit
breakers and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Verify the service hoses are properly attached to
the unit without any restrictions and coupler valves
are open.
4. Verify a deep vacuum has been pulled on the system being charged.
5. Check that all ISV hoses are properly installed and
valves are open. Also verify that the scale is unobstructed.
6. If “INSUFFICIENT REFRIG AVAILABLE” is
on the display, verify that there is a minimum of 8
pounds (3.6 kilograms) of refrigerant in the tank.
If there is enough refrigerant in the tank check scale
calibration and re-calibrate.
7. Verify that the control module has accepted the
programmed amount. Test the operation of the
keypad; replace if necessary.
8. Verify the Low-Side Charge and/or High-Side
Charge solenoids (depending on user input) are
receiving power and opening properly.
• If not receiving power, check the continuity of
the wiring between solenoid and relay board—
repair as needed.
• If the wiring is correct and no power is being
applied to the solenoid, replace the relay
board.
• Verify the solenoid coil is opening the solenoid
properly.
9. Check the Low-Side Inlet, High-Side Inlet, Oil
Inject, and Power Charge solenoids for bleedthrough and proper operation—repair as needed.
If the unit does not complete a full charge, the
compressor, power charge and high-side clear
solenoids are activated, then stop to build
tank pressure.
10. If the proceeding steps fail to repair the problem,
replace the display/control board.
Slow Charge:
1. Check and ensure that there is a good vacuum in
the vehicle being tested.
2. Verify that there is sufficient pressure in ISV to
transfer refrigerant.
3. Ensure chargeable weight is greater than desired
charge.
4. Verify the charge couplers are completely open
and the vehicle ports are actuated.
5. Check for debris in any of the charging circuit
solenoids. Clean or replace if necessary.
52
34788 Service Manual
Diagnostics
Miscellaneous Error Messages
Low Recover Pressure, Check Connections
During the recovery process, the unit is seeing less than
10 psi at the Low-Side Pressure Transducer. Verify all
connections before continuing.
Out of Range Error
When entering the “tank fill level” amount during setup,
you must enter a value between 4-20 lbs. If the value
entered is outside this range, this error message will
be displayed.
Pressure too High for Vacuum
If this message occurs during the evacuation process, the
unit is seeing greater than 10 psi at the Low-Side Pressure Transducer. Perform recovery before continuing.
If this message occurs during the clearing process, the
unit is seeing greater than 10 psi at “any” pressure transducer.
Insufficient Refrigerant Available
The entered charge amount is greater than the amount
in the ISV. Add additional refrigerant to the tank.
Insufficient Refrigerant for Flush
There is less than 10 lbs. of refrigerant in ISV. To perform the flush routine, there must be more than 10 lbs.
of refrigerant available in the tank. Add refrigerant.
Insufficient ISV Pressure for Test
There is less than 50 psi of pressure in the ISV. To perform the leak test routine, the tank pressure must be higher
than 50 psi.
Calibration Error/Calibration Rejected
When the calibration check is performed, the unit measures the scale weight before and after the calibration
weight has been attached to the scale. If the difference
in weight is 1.18 ± 0.03 lbs., the calibration check will
pass. However, if the difference is anything else, the Calibration Error/Calibration Rejected message will be displayed.
UL Cal Error, Check Cal Weight
UL calibration failure has occurred. Verify that scale is
unobstructed and calibration weight is 43 lbs. for
Worthington ISV, or 45 lbs. for the Aircom ISV. Scale
or control board not responding correctly.
Serial Number Error
The 10-digit serial number for the filter was entered incorrectly. Re-enter serial number.
ISV Pressure Error L
The ISV Pressure Transducer is reading tank pressure
less than 30.54 inHg.
ISV Pressure Error H
The ISV Pressure Transducer is reading tank pressure
greater than 460 PSI.
LS Pressure Error L
The Low-Side Pressure Transducer is reading low-side
pressure less than 30.54 inHg.
LS Pressure Error H
The Low-Side Pressure Transducer is reading low-side
pressure greater than 140 PSI.
ACC Pressure Error L
The ACC Pressure Transducer is reading accumulator
pressure less than 30.54 inHg.
ACC Pressure Error H
The ACC Pressure Transducer is reading accumulator
pressure greater than 140 PSI.
ISV Temp Probe Error / Air Purge Not Working
The ISV Temperature Probe is reading tank temperature that is either too low (less than 40° F) or too high
(greater than 200° F). Check tank pressure and air purge
functions.
53
Diagnostics
34788 Service Manual
SERVICE INSTRUCTIONS & CALIBRATION
Replacement Compressor (RA20020) Specifications & Service
Specifications
Compressor Fittings
Make:
Voltage:
Capacity (BTU/HR):
Running Amps:
Speed:
Locked Rotor Amps:
Oil Charge Capacity:
Refrigerants:
POE Oil Type:
Weight w/oil:
Replacements:
1/3 HP Cubigel
115V / 60Hz
5821
8.4A
3500 RPM
30.0A
Initial - 13.5 oz
Recharge - 11.8 oz
R-12, 22, 500, 502, 134a
404a
ISO 22
23.8 lbs.
110V - RA20020
Oil Return
(Intake)
Suction
Discharge
Adding Oil to Compressor
Troubleshooting Compressor
Due to the configuration of the Cubigel suction and discharge fittings, there is no easy method of checking or
removing oil from the compressor.
Compressor Will Not Run
The following procedure is the recommended method
for changing oil in the Cubigel compressor:
1. Connect a refrigerant supply tank to one of the
compressor’s suction ports.
2. Connect a portable recovery unit to the other suction port.
3. Cap the discharge port on the compressor.
4. Run the recovery unit to completely flush all oil
from the compressor.
5. Disconnect everything and add 13.5 oz. of new
oil (ISO 22) to the compressor.
54
1. Check for proper power source, check circuit
breaker and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Verify that the ground wire between the
compressor’s electrical box and chassis ground
is securely fastened.
4. Check for 110 volts to the compressor.
• If there is no voltage to the compressor’s start
components, proceed to next step.
• If voltage is present at the compressor, jumper
the thermal overload. If the compressor runs,
check the compressor amp draw. If it is drawing locked rotor amps or not running, replace
the compressor. If the compressor is cool and
34788 Service Manual
drawing low amperage, replace the thermal
overload.
5. Check for 110 volts from the relay board on connector J6, pins 3 and 4.
• If voltage is present, check wiring between the
relay board and the compressor’s start components. Repair as needed.
• If voltage is not present, replace the relay
board.
• If after replacing the relay board, voltage is still
not present, replace the display/control board.
Diagnostics
6. Shut off the compressor. The suction and discharge values should hold for 30 seconds to one
minute. If not, proceed to step-7, then repeat test.
If no improvement, replace the compressor.
7. If the compressor has weak suction or discharge,
check the oil level and add oil if necessary. If the
oil level is okay or oil was added with no improvement, replace the compressor.
Removing the Compressor
1. Disconnect the unit from its power source.
6. Perform functional check and recalibrate unit.
2. Remove the unit’s door and front panel.
Suction and Discharge Pressure Test
3. Depressurize the unit.
1. Disconnect all fittings from the compressor.
4. Disconnect the copper line from the compressor.
2. Cap the intake fitting.
5. Disconnect the two black tubes from the compressor.
3. Install a low side gauge on the suction fitting.
The fitting used on the suction port is a 3/8”
compression fitting. Use the appropriate
fitting with an R-134a manifold set.
4. Install a high pressure gauge on the discharge fitting.
The fittings used on the discharge port require
an o-ring fitting to seal. Use a 120063 hose
(1/4” flare o-ring X 1/2” ACME Q.S.) with an
R-134a manifold set.
5. Start the compressor and monitor the readings.
The discharge pressure should build to 250 psi
(17.24 bar). The compressor should pull a 25”
(.85 bar) vacuum.
6. Remove and save the four nuts and bolts that secure the compressor into the unit.
7. Disconnect the wires from the main wire harness.
8. Remove the compressor from the unit.
9. Remove the compressor electrical box cover by
releasing the spring clamp that holds it on.
10. Disconnect the wires from the electrical components.
Capacitor may still be energized, so remove
wires with caution.
11. Disconnect the two black tubes from the main
block, and discard.
55
Diagnostics
34788 Service Manual
Replacement Compressor (RA20020) Specifications & Service (continued)
Installing the Replacement Compressor
(Refer to Figures 1 & 2 during this installation)
RETAINER
COMP.
ELEC. BOX
1. Install the four rubber mounts (included in kit) into
the base of the compressor.
PROTECTOR
RELAY
2. Install the electrical components.
3. Connect wiring to the compressor electrical components as shown in Figure 1.
SCREW
CAPACITOR
LEADS
4. Install the compressor electrical box cover, and
secure with the existing spring clamp.
CAPACITOR
5. Place the compressor into the unit.
Figure 1 – Compressor Wiring
6. Place one steel sleeve (included in kit) into each
of the four rubber mounts in the base of the compressor.
Manifold
Assembly
7. Secure the compressor into place with the existing four nuts and bolts.
8. Reconnect the compressor to the wire harness.
15”
9. With the o-rings in place, connect the copper line
to the discharge side of the unit.
10. Refer to Figure 2 and replace the two black tubes
that connect the compressor to the main block
(use tubing from kit RA20005 and ferrules from
kit RA20006).
11. Plug unit into power source, perform a function
test, and check for any leaks.
12. Replace the shrouding.
12”
Compressor
538469
2X 105358
Use Loctite® 242
or equivalent on
threads
Figure 2 – Compressor Tubing Connections
56
Diagnostics
34788 Service Manual
Replacement Vacuum Pump (RA20017) Specifications & Service
Specifications
1/3 HP VacuMaster® Pump
110V
60Hz
4.5 A
Call Tech Support
3 cfm
7.4 oz - 219 ml
Premium Vacuum Pump Oil
Make:
Volts:
Frequency:
Running Amps:
Locked Rotor Amps:
Flow Rate:
Oil Capacity:
Oil Type:
Vacuum Pump Not Running
1. Check for proper power source, check circuit
breaker and check electrical connectors for damage or corrosion.
2. If the unit is being run through an extension cord,
eliminate its use.
3. Check for 110V at the vacuum pump connector,
pins 2 and 3 (see figure below).
• If voltage is present, replace vacuum pump
assembly.
• If voltage is not present, continue to next step.
4. Check for 110 volts from the relay board on connector J6, pins 1 and 2.
• If voltage is present, check wiring between the
relay board and the vacuum pump. Repair as
needed.
• If voltage is not present, replace the relay
board.
• If after replacing the relay board, voltage is still
not present, replace the display/control board.
5. Perform functional check and recalibrate unit.
Removing the Vacuum Pump
1. Disconnect the unit from its power source.
2. Remove the unit’s door and front panel.
3. Install and secure the hood spacers.
4. Depressurize the unit.
5. Remove the two existing nylon lines from the
vacuum pump.
6. Remove and save the bolts that fasten the vacuum
pump to the unit.
7. Disconnect the vacuum pump connector from the
main harness.
8. Remove the vacuum pump from the unit.
Installing the Replacement Vacuum Pump
1. Insert the new vacuum pump into the unit.
2. Secure the vacuum pump to the unit with the bolts
saved from the old pump.
3. Connect the electrical connector from the vacuum
pump into the unit’s main harness.
4. Reconnect the two existing nylon lines.
5. Remove the brass plug from the vacuum pump oil
fill port.
6. Add 5 oz. of oil to the vacuum pump.
7. Plug unit into power source, and perform the steps
to start the vacuum pump.
8. While the vacuum pump is running, add more oil
to the correct fill level in the sight gauge.
9. Replace the brass plug in the fill port.
10. Perform a function test, and check for any leaks.
11. Replace the shrouding, and remove the hood
spacers.
BLACK
HOT
NEUT
GND
WHITE
FILL PORT
GREEN
Vacuum Pump Assembly
57
Diagnostics
34788 Service Manual
Replacement High Pressure Cut-Out Switch (RA19427)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
The high pressure cut-out is a normally closed sensor
designed to shut off the unit if the discharge pressure
reaches 435 ± 10 psi. The switch will reset and close
at 320 ± 20 psi.
The pressure is detected through an orifice in the base
of the sensor. In the normal setting (less than 435 psi on
the orifice), the 1 and 3 contacts are closed. When 435
psi is introduced to the orifice, the pressure forces up
on the drive pin, which then forces the center contact to
disengage the 1 and 3 contacts and engage the 1 and 2
contacts. When this happens, the unit halts operation
and displays a high pressure warning on the display.
Brown Wire
Brown Wire
Replacement Instructions
Follow these steps to replace the high pressure cut-out
switch on your unit.
1. Close the tank valves and depressurize the unit.
2. Turn off the MAIN POWER switch, and unplug
the unit from the power source.
3. Remove the panel(s) or shroud to access the manifold block.
4. Disconnect the wires from the high pressure cutout switch.
5. Carefully remove the high pressure cut-out switch.
6. Clean the fitting by wiping away dirt, grease, and
oil. Apply thread sealant to only the external pipe
threads of the fittings. DO NOT apply thread
sealant to any internal threads.
Thread sealant contains ADHHM-128
anaerobic adhesive and methacrylic ester. If there is skin contact with the
sealant, thoroughly was the skin with soap
and water.
7.
8.
9.
10.
11.
12.
Install the new high pressure cut-out switch.
Reconnect the wires to the new switch.
Plug the unit into the power source.
Open the tank valves.
Operate the unit and check for leaks.
Replace the panel(s) or shroud.
Troubleshooting the High Pressure Cut-Out
High Pressure Cut-Out discontinues operation prematurely.
1. Verify that there are no discharge obstructions.
2. Replace the high pressure cut-out.
High Pressure Cut-Out Switch
58
High Pressure CutOut does not discontinue operation of unit at or below designed pressure.
1. Check the wiring.
2. Replace the high pressure cut-out.
34788 Service Manual
Diagnostics
Replacement Scale Assembly/Magnet (RA20002)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
If scale assembly and UL circuit are not
calibrated, scale can overfill the tank, causing
possible explosion and/or vehicle overcharge.
Instructions
These instructions outline the steps to replace the scale
assembly.
Removing the Scale Assembly
1. Disconnect the unit from its power source.
2. Remove the unit’s door and front panel.
3. Install and secure the hood spacers.
4. Close all three (3) tank valves.
5. Depressurize the unit.
6. Disconnect the liquid hose and vapor hose from
the tank.
7. Disconnect the wires from the air purge solenoid,
tank temperature probe, and pressure transducer.
8. Remove the two (2) bolts that secure the tank to
the scale.
9. Remove the tank from the scale.
10. Remove the four (4) nuts that hold the scale in
place.
11. Remove the ground wire connected to the center
divider of the unit and the harness connected to
the relay board.
Installing the Replacement Scale Assembly
1. Connect the ground wire from the scale to the
center divider.
2. Install the scale into the unit and secure with four
(4) nuts.
3. Thread wire through the center panel, and connect to the relay board.
4. Connect the unit to its power source.
5. Turn the unit on to begin calibration steps.
6. Press the MENU key.
7. Press the DOWN arrow twice to SERVICE
MENU.
8. Press 2-2-0-0.
9. Press the START key.
10. Press the UP arrow twice to CALIBRATE
TANK SCALE.
11. Press the START key, and verify there is no
weight on the scale or anything interfering with the
scale.
12. Press the START key.
13. Place 20 pounds on the scale when prompted;
then, press START.
14. Press the UP arrow to UL CALIBRATION.
15. Press the START key.
16. Place 43 pounds on the scale if using a
Worthington tank, or 45 pounds if using an
Aircom tank.
17. Press the START key.
18. Wait while the unit calibrates the UL circuit and
stops.
19. Remove 2 pounds when the unit prompts you.
20. When the unit shows UL CALIBRATION
COMPLETE, press the STOP key twice.
21. Install the tank on the scale, and secure with two
(2) bolts.
22. Reconnect the air purge solenoid, tank temperature probe, and pressure transducer wires.
23. Reconnect the liquid hose and vapor hose to the
tank.
24. Open all three (3) tank valves.
25. Perform a function test, and check for leaks.
26. Remove the hood spacers, and replace the
shrouding.
59
Diagnostics
34788 Service Manual
Replacement Manifold Block (RA20018)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
Removing the Manifold Block
1. Disconnect the unit from its power source.
15. Remove the bolt located between the two solenoids on the top right side.
16. Remove the liquid, vapor, and tank fill hoses from
the block and save.
Installing the Replacement Manifold Block
(Refer to Figures 1 & 2 during this installation)
1. Install the existing liquid, vapor, and tank fill hoses
into the new block.
2. Install the existing bolt into the hole between the
two solenoids on the top right side.
2. Remove the unit’s door and front panel.
3. Install the existing bolt into the hole in the left corner under the block.
3. Install and secure the hood spacers.
4. Reconnect all wiring as shown in Figure 1.
4. Close all three tank valves.
5. Reconnect the vacuum and vacuum bypass lines
using new ferrules (use ferrules from kit
RA20007).
5. Depressurize the unit.
7. Disconnect the three lines from the compressor.
6. Install a new tube for the oil drain line, and connect to the oil drain solenoid (use RA20005 tubing kit [cut to length], and ferrules from kit
RA20006).
8. Disconnect the compressor oil return tube from
the block and discard.
7. Install a new tube for the compressor suction tube,
and connect it to the block.
9. Disconnect the compressor suction tube from the
block and discard.
8. Reconnect the existing compressor discharge line
to the block.
10. Remove the compressor discharge line from the
block and save.
9. Reconnect the existing three lines to the compressor.
11. Disconnect the oil drain line from the oil drain
solenoid.
10. Reconnect the existing tank liquid and vapor hoses
to the block.
12. Disconnect the vacuum and vacuum bypass lines.
11. Open all three tank valves.
13. Disconnect all wires from the block.
12. Plug unit into power source, perform a function
test, and check for any leaks.
6. Disconnect the tank liquid and vapor hoses from
the tank.
14. Remove the bolt located in the left corner under
the block.
60
13. Replace the shrouding, and remove the hood
spacers.
Diagnostics
34788 Service Manual
Figure 1 – Electrical Connections to Manifold Block
Connection
Label
Harness
539992
RB8
HPS
539991
COMP
64
66
76
539989
RB10
GND (2x)
PUMP
FAN
FAN (2x)
COMP
539990
RB9
RB6
CB (2x)
GND
74
75
539994
RB7
PSJ1
PSJ2
539927
RB11
RB13
S1
S2
S5
S6
S10
S11
S15
539987
RB14
S3
S4
S7
S8
S9
S12
S13
S14
539993
GND
25
539988
RB1
Connection
Relay Board J4
High Pressure Switch
PT20
S5
S6
S7
S10
S3
S12
S1
539989 Comp
Comp Start Relay
Compressor Thermal
Compressor Ground
Relay Board J6
Unit Ground Stud
Vacuum Pump Pigtail
Fan Ground
Fan Terminals
539991 Comp
S11
S2
S4
Relay Board J3
Relay Board J1
Circuit Breaker
Unit Ground Stud
Power Switch Terminal 1
Power Switch Terminal 2
PT21
S9
S8
Manifold Assembly (Top View)
HPS
Relay Board J2
Power Supply J1
Power Supply J2
Relay Board J18
Relay Board J17
Normal Discharge Solenoid
High Side Clear Solenoid
High Side Charge Solenoid
Low Side Charge Solenoid
Recover Solenoid
Tank Fill Solenoid
Air Purge Solenoid
Relay Board J11
Oil Inject Solenoid
Deep Recover Solenoid
High Side Inlet Solenoid
Vacuum Solenoid
Low Side Inlet Solenoid
Power Charge Solenoid
Oil Return Solenoid
Oil Drain Solenoid
S13
S14
Manifold Assembly (Front View)
Unit Ground Stud
Power Cord Bracket
Relay Board J7
All wires must be clear of moving parts, pinch
points, and sharp edges.
61
62
16”
VACUUM PUMP
BLUE TUBE FROM
LOW SIDE GAUGE
BLUE SERVICE HOSE
ROUTE THROUGH HOLES
IN SIDE SUPPORT
RED SERVICE HOSE
ROUTE THROUGH HOLES
IN SIDE SUPPORT
USE LOCTITE 242 OR
EQUIVALENT ON THREADS
19”
BLACK TANK FILL HOSE
ROUTE THROUGH HOLE
IN SIDE SUPPORT
MANIFOLD ASSY
USE LOCTITE 242 OR
EQUIVALENT ON THREADS
OIL INJECT
BOTTLE
RED TUBE FROM
HIGH SIDE GAUGE
ISV ASSEMBLY
USE LOCTITE 242 OR
EQUIVALENT ON THREADS
27”
12”
OIL DRAIN BOTTLE
VACUUM PUMP EXHAUST
SHOULD PROTRUDE
APPROX. 1.5” INTO OIL
DRAIN BOTTLE
23” - CUT END OF TUBE
AT 45° AND INSERT TO
BOTTOM OF BOTTLE
STA-STRAP TUBES TO
SLOTS IN SIDE SUPPORT
WITH (2) 102338
USE LOCTITE 242 OR
EQUIVALENT ON THREADS
28”
MANIFOLD ASSY
538469
2X 105358 USE LOCTITE
242 OR EQUIVALENT ON
THREADS
15”
Diagnostics
34788 Service Manual
Replacement Manifold Block (RA20018) (continued)
Figure 2 – Plumbing Connections to Manifold Block
Diagnostics
34788 Service Manual
Replacement Manifold Solenoid (RA20010)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
Instructions
These instructions outline the steps to replace the existing manifold solenoid.
Installing the Replacement Manifold Solenoid
1. Lubricate the o-rings and threads on the new solenoid assembly.
2. Install the new solenoid assembly into the main
block and hand-tighten.
3. Using a torque wrench, tighten the solenoid assembly to a torque of 75 in. lbs. (±5 in. lbs.).
4. Install the new coil on the new solenoid assembly, and secure with the fastener that holds the coil
in place.
5. Using a torque wrench, tighten the coil retaining
bolt to a torque of 30 in. lbs. (±5 in. lbs.).
Removing the Manifold Solenoid
1. Disconnect the unit from its power source.
6. Reconnect the wires that were disconnected when
removing the old solenoid assembly.
2. Remove the unit’s door and front panel.
3. Install and secure the hood spacers.
4. Depressurize the unit.
7. Plug unit into power source, perform a function
test, and check for any leaks.
8. Replace the shrouding, and remove the hood
spacers.
5. Disconnect the two wires connected to the solenoid that is being replaced.
6. Remove the fastener that holds the coil on the
solenoid, and remove the coil.
7. Remove the solenoid assembly from the manifold
block.
8. Check the manifold block for any debris before
beginning the installation of a new solenoid.
63
Diagnostics
34788 Service Manual
Replacement Display Board (RA20012)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
Instructions
These instructions outline the steps to replace the existing display board.
Removing the Display Board
1. Disconnect the unit from its power source.
2. Rotate the unit’s head assembly into a face down
position.
3. Remove the shoulder brackets and the six (6)
screws securing the back of the head assembly
(see diagram below). Lift the back off.
4. Disconnect all wires from the display board.
5. Remove the four (4) screws holding the display
board in place.
Head Assembly Diagram
64
Installing the Replacement Display Board
1. Install the display board, and secure with four (4)
screws.
2. Connect all wires as shown in diagram on back
of this form.
3. Replace and secure the head assembly’s back
with six (6) screws.
4. Replace the shoulder brackets.
5. Remove the unit’s front panel.
6. Connect the unit to its power source.
7. Turn the unit on to begin calibration steps.
8. Press the MENU key.
9. Press the DOWN arrow twice to SERVICE
MENU.
10. Press 2-2-0-0.
11. Press the START key.
12. Press the UP arrow twice to CALIBRATE
TANK SCALE.
13. Press the START key.
14. Close all three (3) tank valves.
15. Depressurize the unit.
16. Disconnnect the liquid hose and vapor hose from
the tank.
17. Disconnect the wires from the air purge solenoid,
tank temperature probe, and pressure transducer.
18. Remove the two (2) bolts that secure the tank in
place.
19. Remove the tank from the scale, and verify there
is no weight on the scale or anything interfering
with the scale.
20. Press the START key.
21. Place 20 pounds on the scale when prompted;
then, press START.
22. When CALIBRATE TANK SCALE appears,
press the UP arrow to UL CALIBRATION.
23. Press the START key.
24. Place 43 pounds on the scale if using a
Worthington tank, or 45 pounds if using an
Aircom tank.
25. Press the START key.
Continued . . .
Diagnostics
34788 Service Manual
Installing the Replacement Display Board Continued
26. Wait while the unit calibrates the UL circuit and
stops.
27. Remove 2 pounds when the unit prompts you.
28. When the unit shows UL CALIBRATION
COMPLETE, press the STOP key twice.
29. Place the tank on the scale, and secure with two
(2) bolts.
30. Reconnect the tank temperature probe, air purge
solenoid, and pressure transducer wires.
31. Reconnect the liquid hose and vapor hose to the
tank.
32. Open all three (3) tank valves.
33. Perform a function test, and check for leaks.
34. Replace the unit’s front panel.
Display Board Wiring Diagram
65
Diagnostics
34788 Service Manual
Replacement Relay Board (RA20013)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
Removing the Relay Board
1. Disconnect the unit from its power source.
2. Remove the unit’s door and front panel.
3. Install and secure the hood spacers.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
4. Disconnect all wires from the relay board.
5. Remove the screws that secure the relay board in
place.
Instructions
These instructions outline the steps to replace the relay
board.
Relay Board Wiring Diagram
66
34788 Service Manual
Diagnostics
Installing the Replacement Relay Board
1. Install the new relay board, and secure in place
with screws.
2. Connect all wires as shown in diagram.
3. Connect the unit to its power source.
17. Press the START key.
18. Place 20 pounds on the scale when prompted;
then, press START.
19. When CALIBRATE TANK SCALE appears,
press the UP arrow to UL CALIBRATION.
4. Turn the unit on to begin calibration steps.
20. Press the START key.
5. Press the MENU key.
6. Press the DOWN arrow twice to SERVICE
MENU.
21. Place 43 pounds on the scale if using a
Worthington tank, or 45 pounds if using an
Aircom tank.
7. Press 2-2-0-0.
22. Press the START key.
8. Press the START key.
23. Wait while the unit calibrates the UL circuit and
stops.
9. Press the UP arrow twice to CALIBRATE
TANK SCALE.
10. Press the START key.
24. Remove 2 pounds when the unit prompts you.
25. When the unit shows UL CALIBRATION
COMPLETE, press the STOP key twice.
11. Close all three (3) tank valves.
12. Depressurize the unit.
26 . Place the tank on the scale, and secure with two
(2) bolts.
13. Disconnnect the liquid hose and vapor hose from
the tank.
27. Reconnect the tank temperature probe, air purge
solenoid, and pressure transducer wires.
14. Disconnect the wires from the air purge solenoid,
tank temperature probe, and pressure transducer.
28. Reconnect the liquid hose and vapor hose to the
tank.
15. Remove the two (2) bolts that secure the tank in
place.
29. Open all three (3) tank valves.
30. Perform a function test, and check for leaks.
16. Remove the tank from the scale, and verify there
is no weight on the scale or anything interfering
with the scale.
31. Remove the hood spacers, and replace the
shrouding.
67
Diagnostics
34788 Service Manual
Replacement Vacuum Relief Check Valve (RA20015)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
Instructions
These instructions outline the steps to replace the existing vacuum relief check valve.
Removing the Vacuum Relief Check Valve
1. Disconnect the unit from its power source.
2. Remove the unit’s door and front panel.
Installing the Replacement Vacuum Relief
Check Valve
Use a thread sealant that is compatible with
refrigerants such as Loctite® 565 or equivalent.
1. Install the compression fitting into the discharge
side of the new check valve.
2. Install the check valve onto the tee fitting that is
connected to the main block.
3. Connect the nylon line that was removed from the
old vacuum relief check valve.
4. Plug unit into power source, perform a function
test, and check for any leaks.
5. Replace the shrouding, and remove the hood
spacers.
3. Install and secure the hood spacers.
4. Depressurize the unit.
5. Remove the nylon line from the fitting connected
to the check valve.
Main Block
6. Remove the check valve connected to the tee fitting.
7. Remove the compression fitting from the check
valve.
Tee Fitting
Vacuum Relief
Check Valve
(Note direction
of flow arrow)
Vacuum Relief Check Valve Location
68
Diagnostics
34788 Service Manual
Replacement Manifold Check Valve (RA20016)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Installing the Replacement Manifold Check
Valve
1. Lubricate the o-rings on the new check valve.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
2. Install the new check valve into the main block
and hand-tighten.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
3. Using a torque wrench, tighten the check valve to
a torque of 75 in. lbs. (±5 in. lbs.).
4. Plug unit into power source, perform a function
test, and check for any leaks.
Instructions
These instructions outline the steps to replace the existing check valve manifold.
5. Replace the shrouding and remove the hood
spacers.
Removing the Manifold Check Valve
1. Disconnect the unit from its power source.
2. Remove the unit’s door and front panel.
3. Install and secure the hood spacers.
4. Depressurize the unit.
5. Remove the existing manifold check valve that
needs to be replaced.
69
Diagnostics
Replacement 3/8” High Pressure Tube (RA20005)
Unplug the station before beginning service
work. Incorrect use or connections can cause
electrical shock.
Wear safety goggles when working with refrigerants. Refrigerants can cause eye injury.
Disconnect hoses using extreme caution! Pressurized refrigerant may be present in hoses.
Point hoses away from you and anyone nearby.
Instructions
These instructions outline the steps to replace the three
black 3/8” high pressure tubes.
To prevent personal injury and/or equipment damage, always replace tubing that
has been removed from the compressor.
The process of installing and removing
the tubes can stress them, causing them
to leak or fail.
1. Depressurize unit.
2. Disconnect and discard the old tube and ferrule
nuts.
3. Using the old tube as a guide, cut a piece of new
tubing the same length.
4. With new ferrule nuts (from kit RA20006), install
the new tube into the unit. Tighten the nuts until
no leaks are detected.
70
34788 Service Manual
J9
Keyboard
J11
SD Card PCB
J1
Display/Control PCB
Development
Use Only
Scale Ass’y
S15-Air Purge
Temp Probe
J2
539988
539927
539988
539995
Power
Switch
J1
Relay PCB
J2
Circuit
Breaker
539990
Air Purge Trans
Future Use
Power Supply
34788 INTERCONNECT DIAGRAM
539927
539927
539987
539989
539994
539988
539988
ISV Ass’y
539996
539990
122770
539992
539991
Fan
Compressor
Vacuum Pump
HP Switch
S1-N Discharge
S2-HS Clear
S5-HS Charge
S6-LS Charge
S10-Recover
S11-Tank Fill
S3-Oil Inject
S4-Dp Recover
S7-HS Inlet
S8-Vacuum
S9-LS Inlet
S12-Pwr Charge
S13-Oil Return
S14-Oil Drain
Low-Side Trans
Accum Trans
Manifold Ass’y
34788 Service Manual
Diagnostics
SYSTEM WIRING
71
Diagnostics
34788 Service Manual
34788 COMPONENT WIRING
3A CIRCUIT BREAKER
FAN
SCALE ASSEMBLY
POWER CORD BRACKET
ISV ASSEMBLY
CB
15 AMP CIRCUIT BREAKER
MAIN POWER SWITCH
72
34788 CHASSIS
Diagnostics
34788 Service Manual
RETAINER
COMP.
ELEC. BOX
PROTECTOR
RELAY
SCREW
PUMP
CAPACITOR
LEADS
VACUUM PUMP ASSEMBLY
CAPACITOR
COMPRESSOR
Future Use
DB2
Development
Use Only
Keyboard
DB1
DISPLAY/CONTROL BOARD
SD1
RELAY BOARD
SD SLOT
(SD2)
SD ADAPTER BOARD
POWER SUPPLY
73
Diagnostics
MANIFOLD BLOCK ASSEMBLY – TOP VIEW
MANIFOLD BLOCK ASSEMBLY – FRONT VIEW
74
34788 Service Manual
Diagnostics
34788 Service Manual
34788 WIRING HARNESSES
Relay Board Connector Pin-outs
The following chart describes the pinouts for each connector on the relay board. The connector descriptions are: J1from power switch, J2-to 12 volt power supply, J3-to circuit breaker, J4-to high pressure switch, J5-to display/control
board, J6-to vacuum pump, compressor, and fan, J7-to low-side transducer, J8-to temperature probe, J11-to manifold
solenoids, J13-to accumulator transducer, J14- to air pressure transducer, J16-to scale assembly, J17-to manifold
solenoids, J18-to normal discharge solenoid.
Conn
Pin1
Pin2
Pin3
J1
Earth Ground
AC Neutral in
AC Line in
Pin4
J2
AC 110V to 12VPS
Neutral to 12VPS
Earth Ground
12V from 12VPS DC GND
J3
Circuit Breaker
Circuit Breaker
12V fuse
12V fuse
J4
HP Switch
HP Switch
J5
Ground
SPI
SPI
SPI
J6
110V Output Pump
Neutral Pump
110V Output Comp Neutral Comp
J7
5V to LS Xducer
Output from Xducer Ground
J8
Temp Probe
Temp Probe
J11
Pwr Charge Sol
Vacuum Sol
J13
5V to Acc Xducer
Output from Xducer Ground
J14
5V to AP Xducer
Output from Xducer Ground
J16
Exc V to scale
Diff out from scale
Diff out from scale
Ground
J17
Tank Fill Sol
Recover Sol
LS Charge Sol
HS Charge Sol
J18
Norm Discharge Sol Aux
Aux
Aux
LS Inlet Sol
HS Inlet Sol
Pin5
SPI
Pin6
Pin7
Pin8
Deep Rec Sol
Oil Inject Sol
12V to Ctrl Board
110V Output Fan Neutral Fan
Oil Return Sol
Oil Drain Sol
Air Purge Sol
HS Clear Sol
AC Power Cord (122770)
AC POWER CORD (122770)
CONNECTOR #
71
72
73
CONNECTS TO:
Main Pow er SW1 - 2A
Main Ground Stud
Main Pow er SW1 - 1A
75
Manifold 1 Harness (539927)
76
CONNECTS TO:
J-17 Relay Board
J-18 Relay Board
Solenoid - S1 (Tan Wires)
Solenoid - S2 (Black Wires)
Solenoid - S5 (Orange Wires)
Solenoid - S6 (Purple Wires)
Solenoid - S10 (Yellow Wires)
Solenoid - S11 (Pink Wires)
Solenoid - S15 (Gray Wires)
MANIFOLD 1 WIRE HARNESS (539927)
CONNECTOR #
RB13
RB11
S1
S2
S5
S6
S10
S11
S15
Diagnostics
Manifold 1 Harness (539927)
34788 Service Manual
Manifold 2 Harness (539987)
CONNECTOR #
RB14
S3
S4
S7
S8
S9
S12
S13
S14
CONNECTS TO:
J-11 Relay Board
Solenoid - S3 (Blue Wires)
Solenoid - S4 (Light Blue Wires)
Solenoid - S7 (Yellow Wires)
Solenoid - S8 (Red Wires)
Solenoid - S9 (Gray Wires)
Solenoid - S12 (White Wires)
Solenoid - S13 (Purple Wires)
Solenoid - S14 (Orange Wires)
MANIFOLD 2 WIRE HARNESS (539987)
34788 Service Manual
Diagnostics
Manifold 2 Harness (539987)
77
Transducer Wire Harness (539988)
78
CONNECTOR #
RB1
RB2
RB3
RB4
TS
PT20
PT21
PT22
CONNECTS TO:
J-7 Relay Board
J-13 Relay Board
J-14 Relay Board
J-8 Relay Board
Temperature Probe - ISV
Low -Side Transducer - Manifold
Accum Transducer - Manifold
Air Purge Transducer - ISV
TRANSDUCER WIRE HARNESS (539988)
Detail A
Diagnostics
34788 Service Manual
Transducer Wire Harness (539988)
Light Blue
Brown
Green/Yellow
Brown
Compressor/Fan Wire Harness (539989)
Dark Blue
Dark Blue
CONNECTOR #
RB10
COMP
FAN
FAN GND
PUMP
GND
Green/Yellow
CONNECTS TO:
J-6 Relay Board
To Compress Harness (539991)
Fan
Fan Ground
Vacuum Pump Assembly
Chassis Ground
Brown
Green/Yellow
COMPRESSOR/FAN WIRE HARNESS (539989)
34788 Service Manual
Diagnostics
Compressor/Fan Wire Harness (539989)
79
80
Brown
Brown
Green/Yellow
Power Wire Harness (539990)
Light Blue
Brown
CONNECTS TO:
J-3 Relay Board
J-1 Relay Board
15A Circuit Breaker
Ground
Pow er Sw itch #1
Pow er Sw itch #2
POWER WIRE HARNESS (539990)
CONNECTOR #
RB9
RB6
CB
GRN
74
75
Diagnostics
34788 Service Manual
Power Wire Harness (539990)
Brown
Compressor Pigtail Wire Harness (539991)
CONNECTS TO:
To Compressor/Fan Wire Harness (539989)
Compressor Relay
Compressor Protector
Compressor Ground
Green/Yellow
Blue
CONNECTOR #
COMP
64
66
76
COMPRESSOR/FAN WIRE HARNESS (539991)
34788 Service Manual
Diagnostics
Compressor Pigtail Wire Harness (539991)
81
High Pressure Cutout Harness (539992)
82
Brown
CONNECTOR # CONNECTS TO:
RB8
J-4 Relay Board
HPS
High Pressure Cutout Sw itch - Manifold
HIGH PRESSURE CUTOUT SWITCH (539992)
Diagnostics
34788 Service Manual
High Pressure Cutout Harness (539992)
Gray
Brown
Power Supply Harness (539994)
Red
CONNECTOR #
RB7
PSJ1
PSJ2
CONNECTS TO:
J-2 Relay Board
J-1 Pow er Supply
J-2 Pow er Supply
Blue
POWER SUPPLY HARNESS (539994)
34788 Service Manual
Diagnostics
Power Supply Harness (539994)
83
Diagnostics
34788 Service Manual
Interconnect Cable (539995)
INTERCONNECT CABLE (539995)
CONNECTOR # CONNECTS TO:
RB12
J-5 Relay Board
DB1
J-9 Display/Control Board
SD Board Cable (539996)
SD BOARD CABLE (539996)
CONNECTOR # CONNECTS TO:
DB2
J-11 Display/Control Board
SD1
J-1 SD Card Board
SD1
84
DB2
Diagnostics
34788 Service Manual
Ground Wire Harness (539993)
GROUND WIRE HARNESS (539993)
CONNECTOR # CONNECTS TO:
25
Pow er Cord Bracket
GND
Chassis Ground
Green/Yellow
Capacitor Lead (516844)
CAPACITOR LEAD (516844)
CONNECTOR # CONNECTS TO:
A
Compressor Relay (1 or 2)
B
Compressor Capacitor
A
B
Black
Fully Insulated
Terminal
85
Diagnostics
34788 Service Manual
COMPONENT IDENTIFICATION
MANIFOLD BLOCK ASSEMBLY - TOP
LOW SIDE
TRANSDUCER
HIGH-SIDE INLET
LOW-SIDE
SOLENOID
CHARGE SOLENOID
HIGH-SIDE
CHARGE SOLENOID
OIL INJECT
SOLENOID
NORMAL DISCHARGE
SOLENOID
S7
S3
S5 S6
S1
PT20
HIGH-SIDE
CLEAR SOLENOID
S2
S10
S8
POWER CHARGE
SOLENOID
S12
S11
S9
S4
RECOVER
SOLENOID
VACUUM
SOLENOID
PT21
HIGH PRESSURE
SWITCH
TANK FILL
SOLENOID
DEEP RECOVER
SOLENOID
LOW-SIDE INLET
SOLENOID
ACCUM TRANSDUCER
AIR PURGE
SOLENOID
HIGH PRESSURE
SWITCH
UPPER BLOCK
LOWER BLOCK
AIR PURGE PRESSURE
TRANSDUCER
S15
TEMPERATURE
PROBE
HPS
4 PSI RELIEF FOR
VACUUM PUMP
COMPRESSOR
OIL
SEPARATOR
SYSTEM OIL
SEPARATOR
OIL RETURN
SOLENOID
ISV
S13
FILTER DRIER
OIL DRAIN
SOLENOID
S14
MANIFOLD BLOCK ASSEMBLY - FRONT
86
ISV ASSEMBLY
Diagnostics
34788 Service Manual
COMPONENT APPLICATION CHART
Component Application Chart
Norm al Discharge
Solenoid (1)
Tank Fill
Recover
ON
ON
Air Purge
Clearing
Vacuum
Leak Test
Inject Oil
Charge /
Pw r Charge*
I
High-Side Clear
Solenoid (2)
I
I*
Oil Inject
Solenoid (3)
ON
Deep Recover
Solenoid (4)
I
High-Side Charge
Solenoid (5)
P
Low -Side Charge
Solenoid (6)
P
High-Side Inlet
Solenoid (7)
ON
ON
Vacuum
Solenoid (8)
I
ON
Low -Side Inlet
Solenoid (9)
ON
ON
Recover
Solenoid (10)
I
Tank Fill
Solenoid (11)
ON
I
Pow er Charge
Solenoid (12)
I
Oil Return
Solenoid (13)
I
Oil Drain
Solenoid (14)
I
Air Purge
Solenoid (15)
I*
I
ON
I
Vacuum Pum p
ON
Com pressor
ON
ON
ON
Fan
ON
ON
ON
ON
ON
I*
ON
I
ON Intermittently
P
User Programmed
*
Charge/Power Charge Note: If the unit does not complete a full
charge, the compressor, power charge and high-side clear solenoids are activated, then stop to build tank pressure.
87
External
Tank
Tank Fill
Solenoid
Tank Fill
Checkvalve
88
TANK FILL
During the Tank Fill process the compressor,
fan, normal discharge, and tank fill solenoid are
activated. The output state of the tank fill solenoid is controlled to maintain 35 psi in the
accumulator. When the ISV reaches the “target” weight, all components are deactivated.
ENERGIZED
Oil Inject
Bottle
Vacuum
Solenoid
Oil Inject
Solenoid
High Side Inlet
Solenoid
Low Side Inlet
Solenoid
Normal
Discharge
Solenoid
High Side
Gauge
High Side
High Side
Charge Solenoid
Compressor
Oil Separator
Pressure
Relief
Low Side
Low Side
Gauge
Low Side
Charge Solenoid
ISV
Temp
Probe
Pressure
Transducer
Air Purge
Solenoid
Air Diffuser
Low Side Pressure
Transducer
Liquid
INTERMITTENT
DISCHARGE
SUCTION
Recover
Solenoid
Vacuum Pump
Oil Return
Solenoid
Compressor
HS Clear
Solenoid
Clearing Discharge
Checkvalve
Vapor
Recover
Checkvalve
Oil Drain
Solenoid
Filter Drier
High Pressure
Switch
Normal Discharge
Checkvalve
Air Purge
Deep Recover
Solenoid
4 PSI
Relief
Oil Drain
Bottle
System Oil
Separator
Accum
Transducer
Power Charge
Solenoid
Diagnostics
34788 Service Manual
FLOW DIAGRAMS
Tank Fill
External
Tank
Tank Fill
Solenoid
Tank Fill
Checkvalve
RECOVERY PROCESS
During the first stage of the recovery process,
the fan, compressor, normal discharge, recover,
HS and LS inlet solenoids are activated. During the second stage of the recover process,
the vacuum pump, vacuum, deep recover, and
power charge solenoids are activated and the
recover solenoid is deactivated.
ENERGIZED
Oil Inject
Bottle
Vacuum
Solenoid
Oil Inject
Solenoid
High Side Inlet
Solenoid
Low Side Inlet
Solenoid
Normal
Discharge
Solenoid
High Side
Gauge
High Side
High Side
Charge Solenoid
Compressor
Oil Separator
Pressure
Relief
Low Side
Low Side
Gauge
Low Side
Charge Solenoid
ISV
Temp
Probe
Pressure
Transducer
Air Purge
Solenoid
Air Diffuser
Low Side Pressure
Transducer
Liquid
INTERMITTENT
DISCHARGE
SUCTION
Recover
Solenoid
Vacuum Pump
Oil Return
Solenoid
Compressor
HS Clear
Solenoid
Clearing Discharge
Checkvalve
Vapor
Recover
Checkvalve
Oil Drain
Solenoid
Filter Drier
High Pressure
Switch
Normal Discharge
Checkvalve
Air Purge
Deep Recover
Solenoid
4 PSI
Relief
Oil Drain
Bottle
System Oil
Separator
Accum
Transducer
Power Charge
Solenoid
34788 Service Manual
Diagnostics
Recover
89
90
Tank Fill
Checkvalve
AIR PURGE
The air purge solenoid is activated to release
excess pressure from the internal storage vessel. The air purge usually follows the Recover
process.
ENERGIZED
Vacuum
Solenoid
Oil Inject
Bottle
Vacuum Pump
Oil Return
Solenoid
Compressor
Oil Inject
Solenoid
High Side Inlet
Solenoid
Low Side Inlet
Solenoid
Normal
Discharge
Solenoid
High Side
Gauge
High Side
High Side
Charge Solenoid
Compressor
Oil Separator
Pressure
Relief
Low Side
Low Side
Gauge
Low Side
Charge Solenoid
ISV
Temp
Probe
Pressure
Transducer
Air Purge
Solenoid
Air Diffuser
Low Side Pressure
Transducer
Liquid
INTERMITTENT
DISCHARGE
Recover
Solenoid
Oil Drain
Solenoid
Filter Drier
HS Clearing
Solenoid
Clearing Discharge
Checkvalve
Vapor
Recover
Checkvalve
Deep Recover
Solenoid
4 PSI
Relief
Oil Drain
Bottle
System Oil
Separator
High Pressure
Switch
Normal Discharge
Checkvalve
Air Purge
SUCTION
External
Tank
Tank Fill
Solenoid
Accum
Transducer
Power Charge
Solenoid
Diagnostics
34788 Service Manual
Air Purge
External
Tank
Tank Fill
Solenoid
Tank Fill
Checkvalve
CLEARING PROCESS
During the first stage of the clearing process the
normal discharge solenoid and compressor are
activated. The second stage of clearing deactivates the normal discharge solenoid and activates the HS clear and oil return solenoids. When
the accumulator transducer reads less than 9
inHG, all outputs are deactivated.
ENERGIZED
Oil Inject
Bottle
Vacuum
Solenoid
Oil Inject
Solenoid
High Side Inlet
Solenoid
Low Side Inlet
Solenoid
Normal
Discharge
Solenoid
High Side
Gauge
High Side
High Side
Charge Solenoid
Compressor
Oil Separator
Pressure
Relief
Low Side
Low Side
Gauge
Low Side
Charge Solenoid
ISV
Temp
Probe
Pressure
Transducer
Air Purge
Solenoid
Air Diffuser
Low Side Pressure
Transducer
Liquid
INTERMITTENT
DISCHARGE
SUCTION
Recover
Solenoid
Vacuum Pump
Oil Return
Solenoid
Compressor
HS Clear
Solenoid
Clearing Discharge
Checkvalve
Vapor
Recover
Checkvalve
Oil Drain
Solenoid
Filter Drier
High Pressure
Switch
Normal Discharge
Checkvalve
Air Purge
Deep Recover
Solenoid
4 PSI
Relief
Oil Drain
Bottle
System Oil
Separator
Accum
Transducer
Power Charge
Solenoid
34788 Service Manual
Diagnostics
Clearing
91
External
Tank
Tank Fill
Solenoid
Tank Fill
Checkvalve
92
VACUUM PROCESS
The default vacuum time is 10:00 minutes.
When the vacuum process begins, the vacuum
pump is activated. After a 5 second delay, the
vacuum, HS and LS inlet solenoids are also
activated. When the Low-Side transducer
reads > 10 psi, you will be prompted to end the
vacuum process.
ENERGIZED
Oil Inject
Bottle
Vacuum
Solenoid
Oil Inject
Solenoid
High Side Inlet
Solenoid
Low Side Inlet
Solenoid
Normal
Discharge
Solenoid
High Side
Gauge
High Side
High Side
Charge Solenoid
Compressor
Oil Separator
Pressure
Relief
Low Side
Low Side
Gauge
Low Side
Charge Solenoid
ISV
Temp
Probe
Pressure
Transducer
Air Purge
Solenoid
Air Diffuser
Low Side Pressure
Transducer
Liquid
INTERMITTENT
DISCHARGE
SUCTION
Recover
Solenoid
Vacuum Pump
Oil Return
Solenoid
Compressor
HS Clearing
Solenoid
Clearing Discharge
Checkvalve
Vapor
Recover
Checkvalve
Oil Drain
Solenoid
Filter Drier
High Pressure
Switch
Normal Discharge
Checkvalve
Air Purge
Deep Recover
Solenoid
4 PSI
Relief
Oil Drain
Bottle
System Oil
Separator
Accum
Transducer
Power Charge
Solenoid
Diagnostics
34788 Service Manual
Vacuum
Tank Fill
Checkvalve
LEAK TEST PROCESS
High-Side inlet and Low-Side inlet solenoids are
activated to equalize high and low sides of system being serviced. Unit checks low-side transducer for rise in vacuum. (This is not a service
menu test.)
ENERGIZED
Vacuum
Solenoid
Oil Inject
Bottle
Vacuum Pump
Oil Return
Solenoid
Compressor
Oil Inject
Solenoid
High Side Inlet
Solenoid
Low Side Inlet
Solenoid
Normal
Discharge
Solenoid
High Side
Gauge
High Side
High Side
Charge Solenoid
Compressor
Oil Separator
Pressure
Relief
Low Side
Low Side
Gauge
Low Side
Charge Solenoid
ISV
Temp
Probe
Pressure
Transducer
Air Purge
Solenoid
Air Diffuser
Low Side Pressure
Transducer
Liquid
INTERMITTENT
Recover
Solenoid
Oil Drain
Solenoid
Filter Drier
HS Clear
Solenoid
Clearing Discharge
Checkvalve
Vapor
Recover
Checkvalve
Deep Recover
Solenoid
4 PSI
Relief
Oil Drain
Bottle
System Oil
Separator
High Pressure
Switch
Normal Discharge
Checkvalve
Air Purge
PRESSURE
External
Tank
Tank Fill
Solenoid
Accum
Transducer
Power Charge
Solenoid
34788 Service Manual
Diagnostics
Leak Test
93
94
Tank Fill
Checkvalve
INJECT OIL
The inject oil button must be depressed to
activate the oil inject solenoid. Release the
button to deactivate the solenoid. The system being serviced must have a vacuum to
pull oil from the oil inject bottle.
ENERGIZED
Vacuum
Solenoid
Oil Inject
Bottle
Vacuum Pump
Oil Return
Solenoid
Compressor
Oil Inject
Solenoid
High Side Inlet
Solenoid
Low Side Inlet
Solenoid
Normal
Discharge
Solenoid
High Side
Gauge
High Side
High Side
Charge Solenoid
Compressor
Oil Separator
Pressure
Relief
Low Side
Low Side
Gauge
Low Side
Charge Solenoid
ISV
Temp
Probe
Pressure
Transducer
Air Purge
Solenoid
Air Diffuser
Low Side Pressure
Transducer
Liquid
INTERMITTENT
DISCHARGE
Recover
Solenoid
Oil Drain
Solenoid
Filter Drier
HS Clearing
Solenoid
Clearing Discharge
Checkvalve
Vapor
Recover
Checkvalve
Deep Recover
Solenoid
4 PSI
Relief
Oil Drain
Bottle
System Oil
Separator
High Pressure
Switch
Normal Discharge
Checkvalve
Air Purge
SUCTION
External
Tank
Tank Fill
Solenoid
Accum
Transducer
Power Charge
Solenoid
Diagnostics
34788 Service Manual
Inject Oil
External
Tank
Tank Fill
Solenoid
Tank Fill
Checkvalve
CHARGE PROCESS
During the Charge process, the end user may select either high-side charge, low-side charge, or both. When
the charge process gets close to the programmed weight,
the unit slows down. It’ll charge, settle, charge again,
settle, etc. When the charge process is complete, user
must equalize hoses. If the unit does not complete a full
charge, the compressor, power charge and high-side clear
solenoids are activated, then stop to build tank pressure.
ENERGIZED
Oil Inject
Bottle
Vacuum
Solenoid
Oil Inject
Solenoid
High Side Inlet
Solenoid
Low Side Inlet
Solenoid
Normal
Discharge
Solenoid
High Side
Gauge
High Side
High Side
Charge Solenoid
Compressor
Oil Separator
Pressure
Relief
Low Side
Low Side
Gauge
Low Side
Charge Solenoid
ISV
Temp
Probe
Pressure
Transducer
Air Purge
Solenoid
Air Diffuser
Low Side Pressure
Transducer
Liquid
INTERMITTENT
DISCHARGE
SUCTION
Recover
Solenoid
Vacuum Pump
Oil Return
Solenoid
Compressor
HS Clear
Solenoid
Clearing Discharge
Checkvalve
Normal Discharge
Checkvalve
Vapor
Recover
Checkvalve
Oil Drain
Solenoid
Filter Drier
High Pressure
Switch
Power Charge
Solenoid
Air Purge
Deep Recover
Solenoid
4 PSI
Relief
Oil Drain
Bottle
System Oil
Separator
Accum
Transducer
NOTE: If the unit does not complete a full charge, the
compressor, power charge and high-side clear solenoids
are activated, then stops to build tank pressure.
34788 Service Manual
Diagnostics
Charge
95
Diagnostics
96
34788 Service Manual
Service Bulletins
34788 Service Manual
4
S E RV I C E B U L L E T I N S
Place all service bulletins for the 34788 in this section
97
Service Bulletins
98
34788 Service Manual
SPX ROBINAIR
655 Eisenhower Drive, Owatonna, MN 55060
Phone: (800) 822-5561 FAX: (412) 690-2001
TECHNICAL SERVICE BULLETIN
RA19950 Reservoir Installation Kit
SUBJECT:
EQUIP. AFFECTED: 3 CFM Station Pump
ACTION REQUIRED: Informational
HARDWARE
NO:
00201-RA
DATE:
Nov., 2006
AUTHOR: S. Parde
Summary
At the end of 2005, Robinair introduced a new 3 CFM station pump in the following A/C units: 34134Z, 34700Z,
and 342000 (see service bulletin #00198-HW). Until now, if the vacuum pump needed repairing, the complete station pump would have to be replaced. Robinair has released a parts kit (RA19950), which include the
reservoir/head assembly, sight glass parts, oil drain w/cap, inlet/outlet fittings, and oil fill plug. (These parts are
not available separately.) This kit is compatible with both 115V and 230V station pumps.
3 CFM Station Pump Part Numbers
RA19902 — Complete Station Pump, 115V, 60Hz
527849
— Complete Station Pump, 230V, 50Hz
RA19950 — Reservoir Installation Kit (includes removal and assembly instructions)
SPX Ser
vice Solutions
Service
THIS DISCLOSURE TO BE MAINTAINED IN CONFIDENCE.
655 Eisenhower Drive, Owatonna, MN 55060
Phone: (800) 822-5561 FAX: (412) 690-2001
TECHNICAL SERVICE BULLETIN
INFORMATION
New Air Com Internal Storage Vessel (ISV)
SUBJECT:
EQUIP. AFFECTED: Robinair 34788 (and associated models)
ACTION REQUIRED: Informational
NO:
00203-RA
July, 2007
DATE:
AUTHOR: S. Parde
Overview
Robinair Engineering has recently approved a new Internal Storage Vessel (ISV) for use in the 34788 unit,
which is identified as “Air Com.” For the time being, either the new Air Com ISV or the Worthington ISV can
be used in the 34788 unit. However, there are some differences between the two ISV’s that should be noted
to properly set UL and scale calibrations. Refer to tank specifications listed below and be sure you identify the
proper tank and use the corresponding specs to calibrate the unit.
AIR COM ISV “New”
WORTHINGTON ISV
Tag says “Certified by “Air Com Co. Ltd.”
Port ID label has a border around its edges
Tank Tare = 20.50 lbs. (9.30 kg.)
UL Calibration Wt. = 45 lbs. (20.4 kg.)
Tag says “Certified by WORTHJ”
Port ID label has no border around its edges
Tank Tare = 17.50 lbs. (7.94 kg.)
UL Calibration Wt. = 43 lbs. (19.5 kg.)
Figure 1 - Air Com Tank Tag
Figure 2 - Worthington Tank Tag
CERTIFIED BY AIR COM CO. LTD.
CERTIFIED BY WORTHJ
Please note this information in the 34788 service manual, or download the updated service manual
from the Robinair Service Center website.
SPX Ser
vice Solutions
Service
THIS DISCLOSURE TO BE MAINTAINED IN CONFIDENCE.
655 Eisenhower Drive, Owatonna, MN 55060
Phone: (800) 822-5561 FAX: (412) 690-2001
TECHNICAL SERVICE BULLETIN
HARDWARE
Internal Storage Vessel (ISV) Assembly Parts
SUBJECT:
EQUIP. AFFECTED: Robinair 34788 (and associated units)
ACTION REQUIRED: Informational
NO:
00204-RA
Aug., 2007
DATE:
AUTHOR: S. Parde
Overview
Robinair Engineering has recently approved a new Internal Storage Vessel (ISV) for use in the Robinair 34788
unit, which is identified as “Air Com.” For the time being, either the new Air Com ISV or the Worthington ISV
can be used in the 34788 unit. The part numbers shown in the listing below are compatible for both Air Com
and Worthington tanks. If the tank itself is ordered (539477), you will receive the new Air Com tank.
3
4
5
9
10
8
11
2
7
12
6
13
1
ISV ASSEMBLY
Use Loctite 565 on all pipe threads.
Tank Tare Weight:
Worthington: 17.50 lbs. (7.94 kg.)
Air Com:
20.50 lbs. (9.30 kg.)
SPX
Ser
vice Solutions
Service
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
Description
ISV, INTERNAL
FITTING, STRAIGHT
SOLENOID, 12V DC DISCRETE
VALVE, BALL, AIR PURGE
VALVE, BALL, LIQUID
PRESSURE RELIEF, 450PSI
FITTING, TEE, .25FP X .25FP X .25MP
VALVE, BALL, VAPOR
TEMPERATURE PROBE
TRANSDUCER, AIR PURGE
TEE, MALE BRANCH 1/8 NPTF
ORIFICE, UNION .026
MUFFLER, AIR EXHAUST
Qty
1
1
1
1
1
1
1
1
1
1
1
1
1
Part No.
539477
210312
RA20009
539799
539798
RA19499
508690
540322
539472
539229
539654
539804
519605
THIS DISCLOSURE TO BE MAINTAINED IN CONFIDENCE.
655 Eisenhower
Drive,Service
Owatonna,
MN 55060
34788
Manual
Phone: (800) 822-5561 FAX: (412) 690-2001
Service Bulletins
TECHNICAL SERVICE BULLETIN
Display Board Wiring Diagram Error
SUBJECT:
EQUIP. AFFECTED: Robinair 34788 (and associated units)
ACTION REQUIRED: Informational
INFORMATION
NO:
00205-RA
Aug., 2007
DATE:
AUTHOR: S. Parde
34788 Service Manual
The Display Board (RA20012) wiring diagram prints located on pages 21 and 65 of the Robinair 34788 service manual are incorrect. Please refer to the print below for correct wiring orientation.
Please note these changes in the Robinair 34788 service manual.
Display Board Wiring Diagram
102
SPX Ser
vice Solutions
Service
THIS DISCLOSURE TO BE MAINTAINED IN CONFIDENCE.
Labor Rates
34788 Service Manual
5
L A B O R R AT E S
Robinair authorizes a labor charge of 1-1/2 hours to troubleshoot and complete a full function test on units that are
covered under factory warranty (including leak testing). The authorized time for parts replacement is 15 minutes
per part. Some items require an additional amount of time to facilitate installation. These items and their times are
listed below. If repairs are estimated to exceed two (2) hours, prior authorization from Robinair is required.
Part Number
Component
Total Time
RA20018
RA20020
RA20017
Manifold Assembly
Compressor Assembly
Vacuum Pump Assembly
60 minutes
30 minutes
30 minutes
Robinair considers filters to be a consumable item; they are not covered under warranty. This includes
parts and labor.
103
Labor Rates
104
34788 Service Manual
Product Warranty
34788 Service Manual
6
PRODUCT WARRANTY
Robinair Limited Warranty Statement
Rev. November 1, 2005
This product is warranted to be free from defects in workmanship, materials, and components for a period of one
year from date of purchase. All parts and labor required to repair defective products covered under the warranty
will be at no charge. The following restrictions apply:
1. The limited warranty applies to the original purchaser only.
2. The warranty applies to the product in normal usage situations only, as described in the Operating Manual.
The product must also be serviced and maintained as specified.
3. If the product fails, it will be repaired or replaced at the option of the manufacturer.
4. Transportation charges for warranty service may be reimbursed by the factory upon verification of the warranty claim and submission of a freight bill for normal ground service. Approval from the manufacturer must
be obtained prior to shipping to an authorized service center.
5. Warranty service claims are subject to authorized inspection for product defect(s).
6. The manufacturer shall not be responsible for any additional costs associated with a product failure including,
but not limited to, loss of work time, loss of refrigerant, cross-contamination of refrigerant, and unauthorized
shipping and/or labor charges.
7. All warranty service claims must be made within the specified warranty period. Proof-of-purchase date must
be supplied to the manufacturer.
8. Use of recovery/recycling equipment with unauthorized refrigerants or sealants will void warranty.
• Authorized refrigerants are listed on the equipment or are available through the Technical Service Department.
• The manufacturer prohibits the use of the recovery/recycling equipment on air conditioning (A/C) systems
containing leak sealants, either of a seal-swelling or aerobic nature.
This Limited Warranty does NOT apply if:
• The product, or product part, is broken by accident.
• The product is misused, tampered with, or modified.
• The product is used for recovering or recycling any substance other than the specified refrigerant type. This
includes, but is not limited to, materials and chemicals used to seal leaks in A/C systems.
105
SPX Corporation
655 Eisenhower Drive
Owatonna, MN 55060-0995
Phone 800-822-5561
Models: 34788, AC34788, H234788, RA-C34788
Service Manual, Rev. C