PLANNING, INSTALLATION
OPERATION AND MAINTENANCE
COMPRESSOR DESICCATOR UNIT 3C
BT ITEM CODE 074375
MANUFACTURERS TYPE NO. 12450
OPERATING HANDBOOK ISSUE 6
DRALLIM TELECOM
(A DIVISION OF DRALLIM INDUSTRIES LTD.)
MILLWOOD HOUSE,
DRURY LANE,
PONSWOOD INDUSTRIAL ESTATE,
ST. LEONARDS ON SEA,
EAST SUSSEX.
TN38 9BA
TELEPHONE: 44 (0) 01424 205140
FAX: 44 (0) 01424 202140
1
2
LIST OF CONTENTS
SECTION
1
INTRODUCTION
SECTION
2
PRODUCTION SPECIFICATION
2.1
2.2
2.3
2.4
2.5
2.6
SECTION
3
Environmental Considerations
Operational Features
Dry Air Output
Alarm Indications.
Monitoring/Control Features
Test Facilities
INSTALLATION DESIGN
3.1
3.2
3.4
3.5
Introduction
Performance
Suitability for High Flow Installations
Outlet Connection
SECTION
4
ACCOMMODATION REQUIREMENTS
SECTION
5
EQUIPMENT SAFETY
5.1
5.2
5.3
5.4
5.5
SECTION
6
INSTALLATION INSTRUCTIONS
6.1
6.2
6.4
6.5
6.6
6.8
6.9
SECTION
7
WARNINGS
Cautions
Health and Safety & Factories Act
Electricity At Work Regulations
Manufacturers Declaration Of Conformity
General
Compressor Desiccator Unit 3C Installation
Pneumatic Connections
Electrical Connections
Remote Monitoring of Alarms
Commissioning the CDU 3C
Completion of Installation
COMMISSIONING
7.1
7.2
7.3
7.4
7.5
7.6
Visual Inspection
Connection
Humidity Detector Check
Compressor Control Pressure Switch Check
Air Receiver Relief Valve Check
Remote Alarm Check
3
SECTION
8
OPERATING INSTRUCTIONS
8.1
8.2
8.3
8.4
8.5
SECTION
9
TEST FACILITIES
9.1
9.2
SECTION
10
11
12
General
Electrical Description
Test Facility Operation
Pneumatic Description
Test Switch Operation
FAULT DIAGNOSIS AND CORRECTIVE MAINTENANCE
11.1
11.2
11.3
SECTION
Introduction
Use of the Test Facility
OPERATING PRINCIPLES
10.1
10.3
10.6
10.11
10.17
SECTION
General
Switch on Procedures - Introduction
Switch on After Commissioning or Long Periods
of “Down Time”
Switch on After Short Shutdown Periods
Adjusting the Equipment Output Pressure
Introduction
Lamp Replacement
Changing the Compressor Filter
MAINTENANCE
12.2
Maintenance Schedule
Functional Checks
12.3
12.4
12.5
12.6
12.7
12.8
12.9
12.10
12.11
12.12
12.13
12.15
12.16
12.18
12.19
12.20
Introduction
Checking for Leaks
Checking the Output Flowrate
Checking the Compressor Maximum Pressure
Checking the Purge Flowrate
Checking the Air Receiver
Checking the Electrical Wiring
Checking the Humidity Detector System
Testing the Sensing Element
Testing the Circuit Board
Changing the Desiccator Bed Filters
Lower Filters
Upper Filters
Changing the Solenoid Valve Cores
Servicing the Non-Return Valve
Changing the Reactivation Orifice
4
SECTION
13
DIAGNOSTICS
13.1
SECTION
14
REPAIRS
14.1
14.2
14.3
14.4
14.5
14.6
14.7
14.8
14.9
14.10
14.11
SECTION
15
Introduction
Introduction
Fuse Replacement
Compressor Replacement
Fan Replacement
Pressure Gauge Replacement
Running Hours Meter Replacement
Compressor Control Pressure Switch Replacement
Compressor Control Pressure Switch Adjustment
Minimum Pressure Regulating Valve Adjustment
Air Receiver Safety Relief Valve Replacement
Power OFF/ON Rocker Switch Replacement
SPARE PARTS
LIST OF FIGURES
FIG
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
COMPRESSOR DESICCATOR UNIT 12450 (CDU 3C) FRONT
VIEW
COMPRESSOR DESICCATOR UNIT 3C - TOP VIEW
COMPRESSOR PRESSURE GAUGE VENT VALVE
CONTROL FEATURES
ELECTRICAL DIAGRAM
COMPONENT LAYOUT (CONTROL FEATURES)
COMPONENT LAYOUT (DESICCATOR FEATURES)
PNEUMATIC DIAGRAM
USE OF FLOWMETER PORTABLE 2A TO CHECK OUTPUT
FLOWRATE
USE OF FLOWMETER PORTABLE 2A TO CHECK PURGE
FLOWRATE
DESICCATOR BED FILTER ASSEMBLY
SOLENOID VALVE ASSEMBLY
NON-RETURN VALVE ASSEMBLY
COMPRESSOR REMOVAL
COMPRESSOR CONTROL PRESSURE SWITCH
LIST OF TABLES
1
2
3
4
FAULT DIAGNOSIS
MAINTENANCE SCHEDULE
MALFUNCTION DIAGNOSIS
SPARE PARTS
LIST OF DOCUMENT ISSUES
5
SECTION 1 - INTRODUCTION
1.1
The DRALLIM Compressor Desiccator Unit 12450 (CDU 3C) is an energy
saving integrated unit for supplying dry air to pressurised cables. It has been designed to
alleviate the need for gas bottles in smaller exchanges, and is quiet enough in operation
to be sited in manned areas.
1.2
The CDU 3C consists of a small cabinet housing the compressor, desiccator,
humidity detector and all electrical and pneumatic control circuits. An air
receiver forms an integral part of the unit, obviating the requirement for
additional components. However, a pressure regulating panel (Panel Pressure
Regulating 3A) is necessary to control the output from the CDU 3C.
1.3
The CDU 3C can be installed to be either wall or rack mounted using its alternative
bracket positions, or can equally be sited as a floor standing unit if preferred. In some
cases the cabinet may be sited some distance from the Equipment Cable Pressurisation
(ECP) rack. This will not affect the operation of the unit and all details given in this
manual will still be applicable. No on-site installation adjustments are necessary.
1.4
The CDU 3C has been designed for simple installation and requires
little routine maintenance. Up to 8000 running hours, the only part serviced
is the compressor intake filter which is changed by the operator. To maintain
optimum efficiency however, a number of functional checks should be carried
out at 4000 hour intervals. These checks are detailed in Section 12 of this
manual.
1.5
This manual provides information in Sections 11, 12, 13,14 and 15 to
allow personnel to maintain and repair all parts of the system. The only
notable exception is the compressor which is normally replaced as a unit if faulty.
1.6
The pressure figures quoted in this manual are, in general, purely
nominal and must be treated as such. This is because the figures achieved
for individual installations will vary due to design tolerances and other
external factors.
Note
Assuming that the equipment is being serviced as detailed in Section 12 of
this manual, any gross deviations from the given figures should be reported to the
manufacturer.
6
Fig 1 - Compressor Desiccator Unit 12450 (CDU3C) - Front View
SECTION 2 - PRODUCT SPECIFICATION
2.1
Environmental Considerations:
h
Operating Voltage
-
230V A.C. 50HZ single phase
Plug and 2 metre lead supplied
Rating plate affixed to unit
Current consumption 2.1A
h
Temperature
-
Ambient operating temp. 0 to 35°C
h
Dimensions
-
440mm wide x 800mm high x
330mm deep
7
2.2
-
Fixing brackets enable
either wall or 19in. rack mounting
h
Mass
-
55kg
h
Noise Level
-
56 to 59 dBA at 1 metre, all
planes
-
1
Operational Features:
h
Compressor
/3 HP rocking single cylinder
piston pump (100 psi)
Stop/start pressure 32-65 psi
Minimal transmission of
vibration, compressor fitted via
rubber mounts.
Safety relief valve fitted to
protect against overpressure
Intake filter fitted with
replaceable element
-
-
h
Air Drier
-
Twin bed heatless pressure reactivated adsorption type. Each bed
on line 1 min/regenerating l min.
Automatic changeover by
electro-mechanical process timer
with memory
Desiccant, grade 4A molecular
sieve, 3-5mm
Inlet and outlet filtration by
sintered 35 micron bronze filters
at each drier bed port
Output dewpoint detection
circuit with associated indication
& test facilities
Automatic bypass to atmosphere
of any insufficiently dried air.
Set to operate at -20ºC/reset at -25ºC
“Brown” colour coded humidity
Sensing Element
Fail safe operation
-
-
-
h
Humidity Detection
-
h
Dry Air Storage
-
Welded air storage reservoir to
provide reserve of dry air
Capacity 15 litres
Safety relief valve set at 102 psi
with integral ring pull
Fitted with ¼ turn drain ball valve
-
8
2.3
2.4
Dry Air Output:
h
Pressure
-
Unregulated 32/65 psi intended to be
controlled by a separate remote pressure
regulating panel
h
Flow
-
Exceeds 35 cu ft./hr (16.5 litres/min)
Free air delivery
h
Dewpoint
-
Better than -40ºC
h
Connection
-
Single “quick release” bulkhead
coupling to suit ¼“ OD tube, situated
at top rear of equipment.
-
(Multichip Leds) with integral
current limiting resistors.
Receiver Filling (Green)/Dry
Receiver not filling (Red)/Wet
ie output being bypassed to
atmosphere
Alarm Indication:
h
Visual
-
h
Extended
-
15 Way “D” connector provided to
enable remote indication of alarms, both
normally open and normally closed
volt free contacts provided (2 sets each)
for:
Mains fail
Low output pressure.
-
2.5
Monitoring/Control
h
Electrical
-
Combined illuminated on/off switch and
circuit breaker.
Total running hour meter to indicate
compressor usage.
“Running command” lamp indicating
when compressor should be operating.
-
h
Pneumatic
-
63mm dia. “Compressor” pressure
gauge (liquid damped)
63mm dia. “Receiver” pressure
gauge 0-160psi.
-
9
2.6
Test Facilities
h
Element Check
-
A momentary pushbutton switch
introduces un-dried compressor air
to the sensing element
h
Circuit Check
-
“Wet” and “Dry” circuit check
pushbuttons to electrically test
humidity detector circuitry
Tester Humidity Detector 1A
compatible via test jack sockets located
internally
-
h
Override
-
Momentary pushbutton to run
compressor continually enabling tests
to be carried out on the humidity
detector.
SECTION 3 - INSTALLATION DESIGN
INTRODUCTION
3.1
In order to establish the suitability of the CDU 3C for a particular installation, the
following data and information must be considered.
PERFORMANCE
3.2
The unit is capable of delivering in excess of 35 cu. ft/hr (16.5 litres/min.) of dry air at
free air delivery (FAD).
It is recommended that for most applications the unit should run at a maximum duty
cycle of 50% (12 hrs/day); this means that the total flow should ideally not exceed
13 cu. ft/hr (6 litres/min) at 620 mbar supply pressure.
3.3
To find total cable flow of an existing installation, add together the flow
readings of the individual rack mounted flowmeters.
Note
No harm will occur to the equipment if the 50% duty cycle is exceeded, but at these
higher levels, the reserve capacity (which may be required to deal with faults or
emergencies)is reduced and the frequency of routine maintenance increased.
SUITABILITY FOR HIGH FLOW INSTALLATIONS
3.4
The CDU 3C is not recommended for installations where cable flow is likely
to exceed 25 cu. ft/hr (12 litres/min) at 620 mbar. For higher flow installations, the
use of either the CDU 1A or CDU2A is recommended depending on capacity.
10
OUTLET CONNECTIONS
3.5
Dry air stored in the air receiver is at a pressure of 32-65 psi (2.2 - 4.5 bar)
and is reduced to an output pressure of 9 psi (620 mbar) cable pressure at the Panel
Pressure Regulating 3A, which can be fitted to the ECP rack, or the CDU 3C itself using
mounting brackets.
3.6
The Panel Pressure Regulating 3A is fitted with a non-return valve to prevent air being
drained from the cables in the event of disconnection of the air supply.
An air valve is also provided as an entry point for cylinder or mobile desiccator supply
in emergencies.
3.7
An alternative panel is available which has all the features of the PPR 3A, but also
incorporates a 5-way flowmeter, with provision to increase by a further five. This panel
can be obtained directly from Drallim (Part No. 13854) and is supplied complete with
brackets to fit above the CDU 3C in a floor standing situation.
Fig 2 - Compressor Desiccator Unit 3C - Top View
11
SECTION 4 - ACCOMMODATION REQUIREMENTS
4.1
The CDU 3C is supplied complete with a 2 metre mains lead terminated
with a 3 pin 13A plug.
4.2
The dry air outlet is via a quick-release coupling at the top of the cabinet. The mating
connector is supplied terminating in an elbow to which ¼“ OD tubing can be connected
and run to the Panel Pressure Regulating 3A.
4.3
Physical data for the cabinet is as follows:
Height
Width
Depth
Weight
4.4
800mm
440mm
330mm
55 kg
When selecting a site for the CDU 3C, observe the following conditions :
i)
Avoid siting the equipment in locations which experience :
a)
b)
c)
ii)
High ambient temperatures - ideal operating conditions are 0-35ºC
- below zero, the compressor may
experience difficulty in starting and
the diaphragm of the Minimum
Pressure Regulating Valve may
become inflexible.
Acidic fumes which may damage the internal seals of the compressor.
Excessive dust will decrease the performance of the equipment and
increase the amount of maintenance required due to filter restrictions.
Site the equipment within the exchange or repeater station building. The
power room will often provide the most suitable site.
4.5
The equipment must not be sited in a cable chamber.
4.6
The Panel Pressure Regulating 3A should be installed adjacent to the CDU 3C where
possible, but extended distances should not cause any operational problems.
4.7
If necessary, arrange for the installation of a wall-mounted mains socket local to the
proposed equipment position. Supply requirements are 230V A.C. 50 Hz 13A.
4.8
The CDU 3C can be either floor standing, wall or 19” rack mounted. No rear or side
access is required, although some free space must be allowed above the unit to allow the
exhaust air to escape. Alternative positions are provided to allow the fixing brackets to
be mounted to the cabinet sides to suit either rack or wall mounting (Fig 1).
4.9
Much of the installation work can be completed without disturbing the existing
equipment, however at some stage it will be necessary to interrupt the existing air supply
to the cables and arrangements for a temporary supply will be required.
12
SECTION 5 - EQUIPMENT SAFETY
5.1
WARNINGS
COMPRESSED AIR: THE COMPRESSOR DESICCATOR UNIT 12450 IS
CHARGED WITH AIR AT PRESSURES UP TO 100 PSI. UNDER NO
CIRCUMSTANCES SHOULD PERSONNEL ATTEMPT TO DISCONNECT
PIPEWORK, VALVES, ETC. UNTIL THE SYSTEM HAS BEEN FULLY DEPRESSURISED.
VOLTAGES: THE COMPRESSOR DESICCATOR UNIT 12450 OPERATES
USING POTENTIALLY LETHAL VOLTAGES OF UP TO 230V AC. ALL
NORMAL PRECAUTIONS REGARDING ELECTRICAL EQUIPMENT MUST
BE OBSERVED WHEN OPERATING OR WORKING ON THE UNIT.
ENSURE THAT ALL ELECTRICAL SUPPLIES ARE ISOLATED BEFORE
OPENING THE EQUIPMENT TO DISCONNECT SUPPLY WIRES.
5.2
CAUTIONS
Ensure that the air intake/outlet orifices forming part of the casing are
unobstructed.
The compressor becomes hot in operation if prolonged running is encountered. This
may cause localised heating of the equipment casing in the vicinity of the
compressor head. Mind your fingers!
5.3
HEALTH AND SAFETY AND FACTORIES ACT.
THE COMPRESSOR DESICCATOR UNIT 12450 IS FITTED WITH A
PRESSURE VESSEL, REFERRED TO IN THE TEXT AS AN AIR RECEIVER.
THE RELEVANT CERTIFICATE OF TESTING IS INCLUDED WITH EACH
INDIVIDUAL EQUIPMENT PERFORMED AFTER MANUFACTURE AND
VALID FOR 12 MONTHS THEREAFTER.
THE AIR RECEIVER IS MANUFACTURED IN ACCORDANCE WITH BS
EN286 / BS5169 CLASS 3E. IT SHOULD BE RE-INSPECTED ON A
REGULAR BASIS IN ACCORDANCE WITH THE PRESSURE SYSTEMS
AND TRANSPORTABLE GAS CONTAINERS REGULATIONS 1989.
5.4
ELECTRICITY AT WORK REGULATIONS
IN ACCORDANCE WITH THE ABOVE REGULATIONS THIS EQUIPMENT IS
TO BE TREATED AS A PORTABLE ELECTRICAL APPLIANCE AND
SHOULD AS SUCH BE INCLUDED IN ANY PLANNED ROUTINE
ELECTRICAL TESTING TO ENSURE EMPLOYEE SAFETY.
13
5.5
MANUFACTURERS DECLARATION OF CONFORMITY
This equipment is CE marked, indicating that the following Directives have
been considered during its design and manufacture. Where relevant, all necessary
controls have been applied to ensure compliance.
5.5.1 Low Voltage Directive (73/23/EEC)
Implemented in the UK by the Electrical Equipment (Safety)
Regulations 1994 (SI 1994 No.3260) which came into effect on 9
January 1995.
Most electrical equipment designed to be used with voltages of 501000V a.c. and 75-1500V d.c. is covered. It provides for the
equipment to be constructed following good engineering practice
so as not to endanger the safety of people, domestic animals or
property.
5.5.2 Electromagnetic Compatibility Directive (89/336/EEC)
as amended by Directive (92/31/EEC)
Implemented in the UK by the Electromagnetic Compatibility
Regulations 1992 (SI 1992 No.2372) applicable in full as from 1
January 1996.
Covering almost all electrical and electronic appliances, intended to
cover the non-generation of electromagnetic disturbances and
immunity from such disturbances.
5.5.3 Simple Pressure Vessels Directive (87/404/EEC)
Implemented in the UK by the Simple Pressure Vessels (Safety)
Regulations 1991 (SI 1991 No.2749) as amended, which came into
effect on 31 December 1991.
Welded vessels intended to contain air or nitrogen at gauge pressures
above 0.5 bar (7.3 psi) are covered. Vessels intended for export
outside the EEC are excluded however.
A copy of the relevant certificate for the air receiver fitted to this equipment
is supplied with the unit.
5.5.4 Pressure Equipment Directive (97/23/EC)
Implemented in the UK by the Pressure Equipment Regulations 1999
(SI 1999 No.2001) applicable in full as from 29 November 1999.
14
Applies to equipment, be it components or assemblies forming an integral
functional system, subjected to pressures exceeding 0.5 bar.
This equipment forms a “Pressure Equipment Assembly” requiring this
manufacturers declaration to be made. The applicable conformity
assessment procedure is Category 1 Module A. All DRALLIM divisions are
accredited with either ISO9001 or ISO9002 and therefore capable of
categorisation to either Module H or Module D1 respectively, exceeding the
necessary requirements.
It is worthwhile noting that “Pressurised pipes for the containment of
transmission systems, for example electrical power and telephone
cables” are excluded from the Regulations as a whole, reference
Article 13 of Schedule 1 of the regulations. This equipment is
supplied primarily for use as part of such a system.
15
SECTION 6 INSTALLATION INSTRUCTIONS
GENERAL
6.1
Installation of the Compressor Desiccator Unit 3C (CDU 3C) necessitates the
interruption of the air supply to the cables. It may therefore be necessary to arrange
for a temporary air supply to be used to pressurise the cables. However, if there is
sufficient space, the CDU 3C can be installed before existing equipment is
recovered.
Note
Ensure that a mains socket outlet is installed in a position adjacent to the CDU 3C
location.
COMPRESSOR DESICCATOR UNIT 3C INSTALLATION
6.2
Unpack and prepare the unit as follows:
i)
ii)
iii)
iv)
Remove and discard the packaging.
Detach the cabinet door keys from their stowed position on the cabinet
and place in the lock of the front door.
Remove the compressor transit screws and pillars and retain for possible
future use.
The unit is equipped with a glycerine filled 0-150psi compressor pressure
gauge of 63mm diameter. This offers the following advantages over a
conventional gauge:
The liquid absorbs vibration and pressure spikes.
The dampening action of the liquid enables the operator to take
readings during conditions of rapid dynamic loading and
vibration – ideally suited to applications where pulsating
situations are encountered, such as a reciprocating compressor.
The liquid lubricates all moving elements, dramatically reducing
wear in the movement.
This gauge is fitted with a venting valve, which has been closed to
prevent escape of the liquid during transit. It is important that this valve
be opened before use.
Temperature fluctuations during shipment and in the process
application cause the liquid to expand and contract, which in turn
increases/decreases case pressure. Move the valve to the ‘open’ position,
which will release any pressure (or vacuum) which has built up in the case.
The valve can be left in this ‘open’ position.
Fig 3 – Compressor Pressure Gauge Vent Valve.
Valve on compressor pressure gauge shown in ‘closed’ position as shipped. Move the
orange lever through 180° to the ‘open’ position.
16
v)
Ensure that a copy of the manual and the air receiver test certificate have
been included in the package.
vi)
Ensure that the mating connector for the quick release air coupling, a copy
of the CDU 3C manual, the air receiver test certificate and a copy of the
factory test results have been included in the package together with the four
mounting brackets and associated screws.
6.3
Position the CDU 3C ensuring that there is sufficient clearance at the side of
the unit to give access to the transit handles. A space of 100mm should be
allowed for air circulation above the extractor fan outlet. The unit can be
installed to be either free-standing, or wall or rack mounted using the
brackets provided.
Pneumatic connections
6.4
The mating connector for the quick release coupling is terminated in an elbow to
accommodate ¼“ OD tubing. The tubing should be routed from this point to the
inlet of the Panel Pressure Regulating 3A.
Use Tubing Polyethylene ¼“ PVC sheathed from the CDU3C to the Panel Pressure
Regulating 3A.
If the adaptor is unsuitable for local requirements, an alternative can be obtained
from the Manufacturer.
The pressure available at the outlet is between 32 and 65 psi (unregulated), as
indicated by the “Receiver” Gauge.
Electrical Connections
6.5
A wall mounted socket outlet should be available adjacent to the proposed position.
Supply requirements are 230V A.C. 50 HZ 13A.
The unit is supplied with a fixed lead terminated in a 13A 3 pin plug to BS1363,
fitted with a 13A fuse.
A thermal/magnetic overload circuit breaker is incorporated in the illuminated
on/off rocker switch, rated at 10A.
CAUTION
Do not re-use any of the existing tubing as it will possibly be contaminated
with water, oil or other debris.
NOTE
Do not remove or make pipework connections to the ECP rack or cables at this
stage.
17
Remote Monitoring of Alarms
6.6
The CDU 3C is provided with facilities to enable external connections to monitor
important alarm functions as under:
i)
Low Output Pressure
Indicating that the unit is failing to respond to dry air demands due to either
fault with the equipment itself or through increase in air requirements. This
could result in inadequate protection being given to the network being
supplied.
The alarm is set to operate when stored pressure within the receiver reduces
to 1.7 bar (25 psi)
ii)
Mains Failure
Connected to the output side of the on/off switch to provide an alarm should
the power supply to the unit be disrupted, or the equipment switched off or
disconnected from the socket outlet for any reason.
6.7
The alarms can be monitored as either normally open or normally closed, or could
be commoned to provide a single “prompting” alarm.
The output is provided by a 15 way “D” Connector sited at the top left of the
cabinet. To monitor these alarms, connections must be made as follows:
PIN NUMBER
FUNCTION
1
2
3
Mains Fail (1)
Normally Closed
Common
Normally Open
4
5
6
Mains Fail (2)
Normally Closed
Common
Normally Open
7
8
9
Spare
10
11
12
Low Output (1)
Normally Closed
Common
Normally Open
13
14
Low Output (2)
Normally Closed
Common
18
15
Normally Open
These are volt free clean contacts rated at 5A maximum.
Refer to the electrical diagram (12450/B), Fig 5 of this manual
COMMISSIONING THE CDU 3C
6.8
Commission the CDU 3C as detailed in Section 7 - COMMISSIONING
WARNING
VOLTAGES: THE COMPRESSOR, DESICCATOR AND HUMIDITY
DETECTOR OPERATE USING POTENTIALLY LETHAL VOLTAGES OF UP
TO 230V AC. ALL NORMAL PRECAUTIONS REGARDING ELECTRICAL
EQUIPMENT MUST BE OBSERVED. ENSURE THAT ALL ELECTRICAL
SUPPLIES ARE ISOLATED BEFORE OPENING THE EQUIPMENT TO
DISCONNECT WIRES.
WARNING
COMPRESSED AIR: THE COMPRESSOR AND ASSOCIATED EQUIPMENT
ARE CHARGED WITH HIGH PRESSURE AIR. UNDER NO
CIRCUMSTANCES SHOULD PERSONNEL ATTEMPT TO DISCONNECT
PIPEWORK, VALVES, ETC, UNTIL THE SYSTEM HAS BEEN FULLY DEPRESSURISED.
COMPLETION OF INSTALLATION
6.9
Complete the installation by carrying out the following steps:
i)
Disconnect any temporary air supply from the cables and re-connect the
cable air pipework.
ii)
Set the POWER OFF/ON switch of the CDU 3C to ON.
iii)
Adjust the PRESSURE REGULATOR on the PPR 3A to give the desired
output pressure reading, usually 9 psi (620 mbar), indicated on the outlet
pressure gauge.
19
SECTION 7 - COMMISSIONING
The following procedures are to be carried out consecutively unless otherwise stated.
VISUAL INSPECTION
7.1
Perform the following checks:
i)
Visually inspect all pipework and check nuts on pipe couplings for
tightness.
CONNECTION
7.2
i)
The mating elbow connector should be plugged into the quick release
coupling at the air outlet of the CDU 3C.
Ensure that no tubing is connected from this to the PPR 3A at this stage,
so that the output is effectively open to atmosphere.
ii)
Check that the external 230V AC electrical supply for the equipment is
connected and switched on. Plug the mains lead into the supply socket.
iii)
Set the POWER OFF/ON switch to ON. The amber power and running
command lamps will be illuminated and the compressor will start
immediately, causing the compressor gauge to rise to about 60-65 psi (4.1 4.5 bar). The Receiver gauge indication will be zero.
iv)
The red NOT FILLING/WET lamp will probably be lit at this stage,
indicating that the desiccant material in the dryer beds has absorbed moisture
from the atmosphere. The compressor output air will be directed through
the desiccant beds and the excess moisture will be purged to atmosphere.
The air will be heard exhausting through the desiccator dump solenoid valve.
v)
When the desiccant beds have been dried (which could take up to four
hours), the NOT FILLING/WET lamp will be extinguished and the green
FILLING /DRY lamp will light. The unit will change over to direct the
compressor output air via the desiccant beds to the air receiver. All air will
consequently be exhausted to atmosphere via the output quick
release coupling.
Note
When running, the sound of a ‘blast’ of escaping air will be heard at regular
intervals and the COMPRESSOR gauge reading will drop back to about 25 psi (1.7
bar) and then quickly rise back to 60 psi (4.1 bar). This is not a fault, but the air
being switched from one desiccant bed to the other to effect the purging of moisture
from the desiccant, thus keeping the output air dry at all times.
vi)
Run the unit with the green FILLING/DRY lamp lit for at least 10 minutes
before checking the operation of the Humidity Detector.
20
HUMIDITY DETECTOR CHECK
7.3
Carry out the following checks on the humidity detector:
i)
With the FILLING/DRY lamp lit, press the CIRCUIT CHECK/WET
push-button. The NOT FILLING/WET lamp should light and the
FILLING/DRY lamp extinguish, indicating that the associated electrical
circuit is functioning correctly. When the CIRCUIT CHECK/WET
push-button is released, check that the NOT FILLING/DRY lamp lights.
ii)
With the FILLING/DRY lamp lit, press the ELEMENT CHECK pushbutton very briefly. The NOT FILLING/WET lamp should light and the
Compressor gauge reading should drop to about 49 - 52 psi (3.4-3.6 Bar).
After a short time, the WET lamp should extinguish, the FILLING/DRY
lamp being lit in its place. The COMPRESSOR gauge reading should
rise to about 60 - 65 psi (4.1 - 4.5 Bar). This test confirms that the humidity
detector and associated equipment is functioning correctly.
Note
The length of time taken for the equipment to dry out the desiccant beds (hence
lighting the DRY lamp) is directly proportional to the length of the time that the
ELEMENT CHECK button is held depressed. For this reason, do not hold the
button for longer than a few seconds.
COMPRESSOR CONTROL PRESSURE SWITCH CHECK
7.4
i)
Remove the mating elbow connector from the socket of the quick release
coupling at the top of the CDU 3C cabinet. This will prevent compressed
air from the reservoir escaping to atmosphere. The pressure shown on the
RECEIVER gauge will rise to 63 - 67 psi (4.3 - 4.6 Bar) and the
compressor will stop.
ii)
Replace the elbow connector to allow air to be released from the air
receiver. The receiver gauge should slowly fall and the compressor restart at
33 - 37 psi (2.3 - 2.6 Bar). This test confirms that the compressor control
pressure switch is functioning correctly.
AIR RECEIVER RELIEF VALVE CHECK
7.5
Note
To check for the correct operation of the receiver relief valve, it is necessary to
override the compressor control pressure switch which normally has a maximum
setting of 65 psi (4.5 Bar). This is done by depressing and holding in the
OVERRIDE switch.
Proceed as follows to check the air receiver relief valve :
i)
The mating elbow connector should be removed from the quick release
coupling at the air outlet of the CDU 3C.
ii)
Open the hinged front door of the cabinet
21
iii)
Hold the OVERRIDE button in until the air receiver relief valve
opens. Check that the reading on the air receiver pressure gauge is
approx 92 - 112 PSI (6.4 – 7.7 Bar).
REMOTE ALARM CHECK
7.6
Confirm correct operation of the remote alarm monitoring facility either at the
remote site, or directly at the alarm output socket at the top left of the cabinet.
Refer back to Sections 6.6 - 6.7 to identify the pin numbers and their function.
Checking should be carried out as follows:
I)
Confirmation of the Low Output Pressure alarm function can be made by
plugging the mating elbow connector into the quick release coupling at the
air outlet of the CDU 3C. This will exhaust all stored air from the dry air
storage reservoir. The compressor will restart when Receiver pressure drops
to 33 - 37 psi (2.3 - 2.6 Bar), but the pressure will continue to fall, and at 22
- 28 psi (1.5 - 1.9 Bar) the Low Output Pressure alarm will be activated.
ii)
The Mains Failure alarm operation can be checked by switching the
equipment off at the mains socket outlet, or operating the POWER OFF/ON
switch.
Note
Commissioning has now been completed and the POWER OFF/ON switch should
be switched to the OFF position.
22
SECTION 8 - OPERATING INSTRUCTIONS
GENERAL
8.1
The design of the CDU 3C is such that it can be left operating for long periods of
time with a minimum of operator intervention.
SWITCH ON PROCEDURES
Introduction
8.2
Depending on the length of time since the unit was last used, one of two differing
sequences of events may be observed at switch-on. Although the operating
procedure is substantially the same in both situations, both of the sequences are
described in the following text. The operator should decide which test is applicable
to his situation and read the instructions given therein.
Switch-on After Commissioning or Long Periods of ‘Down Time’
8.3
If the equipment has been commissioned and then left idle for some time or has not
been operating due to, say, repair work, the following procedure must be adopted.
i)
Check that the quick release pneumatic connection at the top of the cabinet
has been made.
ii)
Check that the external 230V AC electrical supply for the equipment is
connected and switched on.
iii)
Set the POWER OFF/ON switch to ON. The amber POWER switch and
RUNNING COMMAND lamps will be illuminated and the compressor will
start immediately, causing the COMPRESSOR gauge on the panel to rise to
about 60 psi (4.1 Bar).
iv)
It is probable that the red NOT FILLING/WET lamp will be lit at this
stage. Under these circumstances, this is not a fault indication but is due to
the desiccant material in the dryer beds absorbing moisture from the
atmosphere. Leave the unit running; the compressor output air will be
directed through the desiccant beds and the excess moisture will be purged
to atmosphere. When the desiccant beds have been dried (which could
take up to four hours), the lamp will be extinguished and the green
FILLING/DRY lamp will light.
v)
When the FILLING/DRY lamp is lit, the unit will change over to direct the
compressor output air via the desiccant beds to the air receiver. The gauge
labeled RECEIVER will be seen to rise slowly until a pressure of 65 psi (4.5
Bar) is obtained, the compressor will then be switched off.
23
Note
When running, the sound of a ‘blast’ of escaping air will be heard at regular
intervals and the COMPRESSOR gauge will drop to about 25 psi (1.7 Bar) and then
quickly rise back to 60 psi (4.1 Bar). This is not a fault, but is the air being
switched from one desiccant bed to the other to effect the purging of moisture from
the desiccant, thus keeping the receiver air dry at all times.
vi)
Check for any leaks in the interconnecting pipework and connectors and
rectify as necessary.
vii)
Check that the visual indicator of the RUNNING HOURS meter is
revolving, indicating that the meter is operating correctly.
viii)
Carry out the test procedure detailed in Section 9.
Fig 4 - Control Features
24
Switch on After Short Shutdown Periods
8.4
If the equipment has been switched off for only a short time, perhaps to allow
routine maintenance, the following procedure must be adopted.
i)
Check that the quick release pneumatic connection has been made at the top
rear of the cabinet.
ii)
Check that the external 230V AC electrical supply for the equipment is
connected and switched on.
iii)
Set the POWER OFF/ON switch to ON. The amber POWER switch
lamp will be illuminated. If the air receiver is below 35 psi (2.4 Bar), the
compressor will start and the COMPRESSOR pressure will rise to 60 psi
(4.1. Bar). If the compressor does not start, this usually means that the
pressure at the receiver is already adequate.
Note
When running, the sound of a ‘blast’ of escaping air will be heard at regular
intervals and the COMPRESSOR gauge will drop to about 25 psi (1.7 Bar) and then
quickly rise back to 60 psi (4.1 Bar). This is not a fault, but is the air being
switched from one desiccant bed to the other to effect the purging of moisture from
the desiccant, thus keeping the receiver air dry at all times.
iv)
Check for any leaks in the interconnecting pipework and connectors and
rectify as necessary.
v)
Check that the visual indicator of the RUNNING HOURS meter is
revolving, indicating that the meter is operating correctly.
vi)
Carry out the test procedure detailed in Section 9.
ADJUSTING THE EQUIPMENT OUTPUT PRESSURE
8.5
From time to time, it may become necessary to adjust the system output pressure if
the flow demand has been radically altered in some way. In the majority of
applications, the pressure regulating panel should be adjusted to provide an output
pressure of 9 psi (620 mbar) indicated by the output pressure gauge. This pressure
will then be maintained irrespective of the pressure in the air receiver, provided that
the receiver pressure is greater than 20 psi (1.4 Bar).
25
SECTION 9 - TEST FACILITIES
INTRODUCTION
9.1
The CDU 3C is provided with a test facility which may be used by the operator to
check that the system is functioning correctly. It is good practice to operate this
facility at regular intervals as a “confidence check”, even if the equipment is
apparently working normally.
USE OF THE TEST FACILITY
9.2
At the prescribed intervals, initiate a test of the equipment as detailed below.
9.2.1
If the compressor is not running, hold in the OVERRIDE
switch. This will bypass the pressure switch and cause the
compressor to start.
9.2.2
If the FILLING/DRY lamp is lit, press the CIRCUIT CHECK/WET
pushbutton. The NOT FILLING/WET lamp should light and the
FILLING/DRY lamp extinguish, indicating that the associated
electrical circuit is functioning correctly.
9.2.3
If the NOT FILLING/WET lamp is lit, press CIRCUIT
CHECK/DRY. The FILLING/DRY lamp should light and the
NOT FILLING/WET lamp extinguish, testing the circuit as in
9.2.2 above. If the NOT FILLING/WET lamp remains on for a
long period this is indicative of a fault.
9.2.4
If condition 9.2.2 exists, press the ELEMENT CHECK pushbutton
momentarily. The NOT FILLING/WET lamp should light and the
COMPRESSOR gauge should drop to about 50 PSI (3.4 Bar). After
a short time the WET lamp should extinguish, the FILLING/DRY
lamp being lit in its place. The COMPRESSOR gauge should
rise to about 60 psi (4.1 Bar). The test confirms that the humidity
detector and associated equipment is functioning correctly.
NOTE
The length of time taken for the equipment to dry out the desiccant beds (hence lighting the
DRY lamp) is directly proportional to the length of time that the ELEMENT CHECK
button is held depressed. For this reason, do not hold the button for longer than a few
seconds.
26
SECTION 10 - OPERATING PRINCIPLES
GENERAL
10.1
The CDU 3C serves to supply dry, compressed air to pressurised cables. Air is
drawn into the cabinet through the louvres in the front door and pressurised by the
compressor. The air is subsequently dried by desiccator beds fitted to a panel on the
inside face of the door and directed to the air receiver. This is fitted at the base of
the cabinet and stores air at between 35 psi (2.4 Bar) and 65 psi (4.5 Bar), allowing
the compressor to operate intermittently in order to maintain this pressure. It also
provides a (15 litre) reserve capacity of air allowing cable pressure to be maintained
for short periods in the event of the CDU 3C being switched off for maintenance.
10.2
The Pressure Regulating Panel (PPR 3A) regulator ensures that the equipment
provides a substantially constant air pressure to the cables irrespective of flow rate.
Notes
1)
Although the electrical and pneumatic diagrams are separated, the two are
obviously inter related. In the following text, references to pneumatic
equipment are found in the electrical description and vice versa.
2)
The descriptions below assume that, at switch on, the CDU 3C operates
correctly and is running dry.
ELECTRICAL DESCRIPTION
10.3
Mains power is applied to the unit by setting the POWER OFF/ON rocker (CBR) to
ON. This switch is a combined thermal/magnetic circuit breaker (giving 10A
overload protection) and neon. The neon is automatically illuminated on operation.
10.4
Assuming that the compressor is required to run, the compressor pressure switch is
closed and the RUNNING COMMAND lamp (LP1) is illuminated.
10.4.1 Power is provided to the compressor and extraction fan.
10.4.2 The compressor RUNNING HOURS meter (HCR) starts and runs
continuously at all times that the compressor is switched on.
10.4.3 Power is provided to the motor of the process timer (PT1). Depending on
the cam position of the timer, power is routed via the wiper to either bed
changeover solenoid valve (SV1 or SV2).
27
Fig 5 - Electrical Diagram
28
10.4.4
10.5
Power is routed to supply the humidity detector (HD) printed circuit
board. According to the condition detected by the sensing element,
the board provides an output to illuminate the NOT FILLING/WET
lamp (LP3) or the FILLING/DRY lamp (LP2) as appropriate.
If the humidity detector senses a “wet” condition, relay contacts are opened to deenergise the by-pass solenoid valve (SV3), expelling the moist air from the
desiccator beds to atmosphere.
TEST FACILITY OPERATION
10.6
When the OVERRIDE switch (SW4) is closed, ie held depressed, the compressor
pressure switch is effectively short circuited, causing the compressor and associated
equipment to operate continuously.
10.7
When the ELEMENT CHECK switch (SW1) is subsequently operated, the wet air
test solenoid (SV4) is energised. As detailed in the pneumatic description (Para
10.11), this causes wet air direct from the compressor to be routed to the sensing
element (HS) simulating a NOT FILLING/WET situation and thus testing the
humidity detector circuit.
10.8
When the DRY CIRCUIT CHECK switch (SW2) is operated, two resistors are
connected in series within the humidity detector board. This simulates the high
impedance normally measured across the dry sensing element. Providing that the
detector circuit is operating correctly, the FILLING/DRY lamp (LP2) will be
illuminated.
10.9
When the WET CIRCUIT CHECK switch (SW3) is operated, only one resistor is
connected within the detector board, presenting the much lower impedance normally
measured across a wet sensing element. Providing that the detector circuit is
operating correctly, the NOT FILLING/WET lamp (LP3) will be illuminated.
10.10 The Humidity Detector Board is fitted with two Jack sockets, JK1 and JK2, which
are used in conjunction with a Tester Humidity Detector 1A as detailed in Section
12 of this manual. Inserting the plug of the tester into JK1 and JK2 disconnects the
sensing element or the circuit board respectively from the equipment, thus allowing
simulated inputs to be applied to test the element and board.
29
Fig 6 - Component Layout (Control Features)
30
Fig 7 - Component Layout (Desiccator Features)
31
PNEUMATIC DESCRIPTION
Notes
1)
The following text assumes that the compressor is running as described in
Para 10.4.
2)
A typical situation when the CDU 3C is first switched on for normal
operation is shown in Fig. 8. The text describing fault and test conditions
assumes that the reader is able to visualise the diagram with the solenoids
SV1 and SV2 in their alternative positions.
10.11 Under normal operating conditions, the filtered high pressure outlet air from the
compressor is routed to an aftercooler, before entering the input solenoid valves to
the two desiccator beds.
10.12 The two input solenoid valves SV1 and SV2 assume opposite positions, i.e. one
energised and the other de-energised. Assuming that the situation is that shown in
Fig. 8, the pressurised air passes through solenoid valve SV1 and into the bottom of
the corresponding desiccator bed (BED 1), where it is filtered and dried.
10.13 At the outlet of the desiccator bed, most of the air passes through the associated
non-return valve into the humidity sensing unit housing (HS). However, a
proportion of the air passes via the reactivation orifice (which is essentially a small
bore restrictor) into the top of the right hand desiccator bed (BED 2). This dry air
passes down through the bed carrying most of the moisture from the molecular sieve
desiccant with it. At the bottom of the bed, the moist air is routed through the
solenoid valve (SV 2) to be discharged to atmosphere.
10.14 Dependent on the operational environment the amount of moisture discharged from
the desiccator will vary. Small amounts of moisture discharged into the cabinet will
be evaporated by the internal heat of the unit.
10.15 The air that has passed through the humidity sensor is next routed to a pressure
maintaining valve (PMV) which maintains a pre-set minimum outlet pressure. If the
humidity sensor has not detected a “wet” condition, the air is directed to the air
receiver. If, however, wet air is detected, the bypass solenoid valve (SV 3) is deenergised, releasing the air to atmosphere.
10.16 After one minute, the electrical process timer (PT 1) changes over the solenoid
valves such that the main air is now routed via the right hand desiccator bed (BED
2) whilst the left hand bed (BED 1) is purged of moisture. One minute later the
timer changes over the valves again and this procedure is repeated indefinitely for
the whole period that the compressor is running.
TEST SWITCH OPERATION
10.17 When the control panel ELEMENT CHECK (SW 1) button is pressed the two way
test solenoid valve (SV 4) is energised. The compressor outlet air will then be
routed directly to the humidity sensing unit housing (HS). Assuming that the
electrical detection system is operating correctly the NOTFILLING/WET indicator
(LP 3) will illuminate and the wet air is dumped as described in para 10.15.
32
Fig. 8 Pneumatic Diagram
33
SECTION 11 - FAULT DIAGNOSIS AND CORRECTIVE MAINTENANCE
Introduction
11.1
In the event that a fault occurs on the equipment, reference should first be made to
table 1. Having diagnosed the fault, refer to the relevant text indicated in the
‘Remedy’ column of table 1.
Notes
1)
If table 1 does not provide a solution for the fault or if the fault recurs, the
manufacturer should be consulted as the fault will probably be beyond user
repair.
2)
In some cases a cross reference is not given in the ‘Remedy’ column if the
work requires no specialist knowledge. e.g. changing a fuse.
TABLE 1 - FAULT DIAGNOSIS
SYMPTOMS
POSSIBLE
FAULT
REMEDY
Relevant lamp does not
light.
Lamp failed
Replace lamp (see paragraph
11.2)
Compressor runs
continuously
Failed or incorrectly set
pressure switch
Replace/adjust pressure
switch (see paragraph 14.7 14.8).
Unit does not run and
POWER switch not lit
a) Mains blown in plug
or
b) Main supply failed
a) Replace fuse (13A) in
mains plug
b) Consult relevant
maintenance authority
Humidity Detection Circuit
not operational
Fuse blown
a) Replace fuse
(see para. 14.2)
34
Lamp replacement
11.2
If it is necessary to replace a failed lamp, the following procedure must be
adopted:
I)
Set the POWER OFF/ON switch to OFF.
ii)
Unscrew the lens of the relevant lamp unit and withdraw the bulb. The
fitting of a new lamp is a reverse operation. The lamps are multichip l.e.ds
with integral current limiting resistors, coloured red or green according to
function.
Changing the Compressor Filter
11.3
i)
Set the POWER OFF/ON switch to OFF.
ii)
Unlock and open the hinged front door of the cabinet to give access to
the compressor.
iii)
Remove the filter unit cover by twisting anti-clockwise and pulling it off.
iv)
Take off the felt filter and discard it.
v)
Using a soft lint-free cloth, wipe out any dust from inside the filter unit
cover. Take care that the nylon disc inside the cover is not lost or
damaged.
vi)
Fit a new felt filter and re-fit the cover, ensuring that it is correctly
locked on.
vii)
Close and lock the front door and set the POWER OFF/ON switch to
ON.
35
SECTION 12 - MAINTENANCE
12.1
The maintenance procedures required on the CDU 3C mainly consist of replacing
items which may have mechanically worn or deteriorated due to age. In order to
maintain the unit operating at full efficiency, the servicing intervals and tasks
detailed in Table 2 should be strictly adhered to.
Note
Before carrying out maintenance on the unit, it is advisable to arrange for a
temporary alternative dry air source to ensure continuity of supply to the cables.
MAINTENANCE SCHEDULE
12.2
Table 2 below is the full routine maintenance schedule for the CDU 3C.
TABLE 2 - MAINTENANCE SCHEDULE
TIME INTERVAL (HOURS)
TASK
4000
8000
12000
16000
Functional check
(Paragraphs 12.3 - 12.12)
*
*
Change desiccant bed filters
(Paragraphs 12.13 - 12.17)
*
*
Change solenoid valve cores 1
(Paragraph 12.18)
*
Service non-return valve
(Paragraph 12.19)
*
*
Change reactivation orifice
(Paragraph 12.20)
Change compressor filter
(Paragraph 11.3)
1
*
*
*
*
*
The frequency of replacement of the wet air test (SV 4) and bypass (SV 3) solenoid
valves is less than that for the desiccator bed changeover valves (SV 1 and SV 2)
36
FUNCTIONAL CHECKS
Introduction
12.3
At the specified time intervals, all of the following functional checks should be
carried out in the order given. If the result of a check is not necessary, refer to
Section 13 - DIAGNOSTICS.
Checking for Leaks
WARNING
THE FOLLOWING TEST REQUIRES THE UNIT TO BE INSPECTED WHILST
IT IS OPERATING. TAKE GREAT CARE AS VOLTAGES OF UP TO 230V AC
AND COMPRESSED AIR AT UP TO 100 PSI ARE PRESENT.
12.4
All pneumatic pipework and unions should be checked for leakage as follows:
i)
The POWER OFF/ON switch should be set to OFF.
ii)
Unlock and open the hinged front door to allow access to the desiccator and
compressor assemblies.
iii)
Set the POWER OFF/ON switch to ON. Confirm that the cooling fan is
running by placing a hand over the louvres in the cabinet top.
However this will only operate whilst the compressor is running and
therefore the OVERRIDE button should be operated if the compressor does
not run.
Note
Discharge the air receiver by using the safety relief valve ringpull which will allow
the unit to operate. This may need to be repeated several times.
WARNING
TAKE GREAT CARE. THE ASSEMBLY WILL NOW BE ELECTRICALLY
LIVE AND PRESSURISED
iv)
Inspect all pipework and fittings for leaks, paying particular attention to
flexible pipework. Larger leaks will usually be audible and self evident. If
a leak is suspected but cannot be confirmed audibly, apply a small quantity
of Leak Detecting Solution.
WARNING
TAKE GREAT CARE WHEN USING LEAK DETECTING SOLUTION NEAR
ELECTRICAL TERMINALS AND WIRING
37
Checking the Output Flowrate
12.5
The Flowmeter Portable 2A is used to check the overall flowrate at the output of the
CDU 3C. To use the flowmeter, proceed as follows:
i)
Refer to Fig 9. Remove the tubing connecting the unit to the Panel Pressure
Regulating 3A. Connect the flowmeter to the output connector on top of the
unit using ¼“ OD tubing.
Fig 9 - Use of Flowmeter Portable 2A
to Check Output Flowrate
ii)
Set the POWER OFF/ON switch to ON and, holding the flowmeter
upright, note the reading obtained. It should be a minimum of 32 cu. ft./hr
(15 litres/min.)
iii)
Set the POWER OFF/ON switch to OFF, remove the flowmeter and
reconnect the normal outlet pipework.
38
Checking the Compressor Maximum Pressure
12.6
Although the compressor is capable of running at higher pressures, the back
pressure of the desiccator is set at 60 - 65 psi (4.1 - 4.5 Bar) to maintain efficiency.
The compressor is controlled such that maximum flow is obtained whilst
overcoming this back pressure. To check the correct running pressure of the
compressor, proceed as follows :
i)
Set the POWER OFF/ON switch to ON. If the compressor does not
start, discharge the air receiver by using the safety relief valve.
ii)
Compressor pressure will rise to 60 psi (4.2 Bar) at which point air will
begin to enter the receiver. The RECEIVER gauge can be seen to rise at this
point. COMPRESSOR pressure should maintain at approximately 60 psi
whilst RECEIVER pressure is increasing.
iii)
A safety relief valve is fitted to the compressor head which is set to
exhaust at 120 - 130 psi (8.3 - 9 Bar)
Checking the Purge Flowrate
12.7
A portable flowmeter 2A is used to check the purge air flowrate at the base of the
desiccator beds. To use the flowmeter, proceed as follows:
i)
With the power still switched off, unlock and open the door.
ii)
Connect the flowmeter inlet pipe (refer to Fig. 10) to the spigot adapter at
the exhaust port of the right hand bed changeover solenoid (SV 2) and ensure
that it is tightened securely.
iii)
Set the POWER OFF/ON switch to ON. If the compressor does not start
immediately, discharge the air receiver by using the safety relief valve. With
the flowmeter held upright, the reading obtained should be in the range 16 20 cu. ft./hr (7.7 - 9.6 litres/min) at NTP.
Note
It may be necessary to wait for up to one minute before it is possible to take a
reading. This is because the desiccator beds are purged alternately under control of
the electrical timer. If more than one minute elapses and the bed has not purged, this
is indicative of a fault in the solenoid and/or timer.
v)
Disconnect the flowmeter.
vi)
Repeat ii) - v) on the left hand bed/changeover solenoid (SV 1)
39
Checking the Air Receiver
12.8
Check that the receiver relief valve is not ‘lifting’ allowing pressurised air to
escape. A serious leak can usually be detected audibly but if in doubt, use a
suitable leak detecting solution. Replace the valve if it is found to be leaking.
Checking the Electrical Wiring
12.9
Check the electrical wiring as follows:
i)
Switch the power OFF at the wall socket outlet.
ii)
With the power OFF, open the hinged door.
iii)
Examine the wiring harness for signs of overheating such as charring or
discoloration.
iv)
Examine the tags on the terminals to ensure that they are secure.
v)
Close and re-secure the door.
vi)
Switch the power ON at the wall socket outlet.
Checking the Humidity Detector System
12.10 When available, a Tester Humidity 1A can be used to test the CDU 3C
internal humidity detection system and can be used in two different modes. In
one mode it tests the humidity sensing element; in the second mode it tests the
circuit board and wiring associated with the element. The use of the meter in
both applications is detailed below. The front door must be open to access the jack
sockets, which are fitted to the Humidity detector circuit board, identified on its
cover as JK1 and JK2.
12.11 Testing the Sensing Element
To test the sensing element, proceed as follows :
i)
Turn the Tester on and connect the small jack plug of the tester lead to the
tester socket marked ELEMENT. Connect the other end of the lead to Test
Jack Socket JK1 (large) of the CDU 3C’s Humidity Detector circuit board.
ii)
Note the reading given on the front panel OHMS meter, which should
be in excess of 50 M ohms.
iii)
If a significantly lower reading is obtained, it may well be that the unit
genuinely being subjected to moist air, switch the CDU 3C on and
leave it to run for 30 minutes before repeating the test. If the element
subsequently gives a reading of less than 50 M ohms when dry, it is
faulty and should be replaced.
iv)
Disconnect the lead from Test Jack socket JK1.
40
is
12.12 Testing the Circuit Board
To test the humidity sensing circuit board and wiring, proceed as follows :
i)
Connect the large jack plug of the tester lead to the tester socket
labelled HUMIDITY DETECTOR. Connect the other end of the tester
lead to Test Jack socket JK2 (small) of the CDU 3C’s Humidity Detector
circuit board.
ii)
Set the tester thumbwheel controls to 150, representing a resistance of
15 M ohms.
Note
The maximum resolution of the thumbwheel resistance controls is 0.1 M ohms.
iii)
Set the CDU 3C POWER OFF/ON switch to ON. If the compressor is
not running depress and hold the OVERRIDE pushbutton. This will
override the pressure switch and cause the compressor to start. Irrespective
of the actual moisture content in the desiccator beds, the front panel
FILLING/DRY (LP 2) lamp should be illuminated.
iv)
Set the thumbwheel controls to 099 (9.9 M ohms) and then
progressively reduce the resistance in 0.1 M ohm steps until the front
panel lamps change to indicate NOT FILLING/WET (LP 3 illuminated).
Note the value at which the lamps change over.
v)
Reset the thumbwheel controls to 199 (this will reset the circuit) and
repeat (iv) twice, noting the changeover value on each occasion. The
average value of the three readings obtained should not be less than
7 M ohms (070).
vi)
Set the thumbwheel controls to 050 (5 M ohms) and check that the
NOT FILLING/WET lamp illuminates. Progressively increase the
resistance in 0.1M ohm steps until the front panel lamps change to
indicate FILLING/DRY. Note the value at which the lamps change
over.
vii)
Reset the thumbwheel controls to 050 and repeat (vi) twice, noting
the changeover value on each occasion. The average value of the
three readings obtained should not be greater than 14 M ohms.
viii)
If the readings listed above cannot be obtained alter the Potentiometer
marked R17 on the electronic circuit board, turn the Potentiometer in
90 degree steps clockwise or anti-clockwise repeating Sections (iii) to
(vii) until correct readings are obtained.
The cover must be removed to gain access to this potentiometer.
41
Note
If the correct readings cannot be obtained the electronic circuit board may be
faulty and will need changing.
Drallim Reference for the electronic circuit board is 13970/110AC/240AC.
ix)
Switch off the CDU 3C and Tester.
CHANGING THE DESICCATOR BED FILTERS
Introduction
12.13 To change the desiccator bed filters, proceed as follows:
i)
Set the POWER OFF/ON switch to OFF.
ii)
Release the air outlet coupling from the quick release connector at the top
of the cabinet.
WARNING
THE AIR RECEIVER AND ASSOCIATED FITTINGS AND TUBING ARE
NOW PRESSURISED AT UP TO 100 PSI. CAUTION SHOULD BE
EXERCISED WHILST CARRYING OUT THE FOLLOWING.
iii)
Pull on the ringpull of the safety relief valve fitted to the air receiver
thus causing it to de-pressurise. Hold it out until the RECEIVER
gauge falls to zero and then release.
12.14 In order to replace the desiccator bed filters, it is first necessary to remove the
desiccator bed as follows.
i)
Fully slacken the ¼" union nuts at the base of the desiccator beds to release
the lower tubing branch, complete with solenoid valves.
ii)
Slacken the two banding strips securing the right hand desiccator bed to its
mounting brackets.
42
Fig 10 - Use of Flowmeter Portable 2A
to check Purge Flowrate
Filter Adaptor
12500/19
O Ring
200-112-4490
Spigot
Adaptor
12500/18
Desiccator
Bed
12500/15/3
Filter
1225501
O Ring
200-019-9775
Fig 11 - Desiccator Bed Filter Assembly
43
iii)
Undo the right hand ¼“ union nut of the tee coupling connected to the
upper filter carrier whilst supporting the desiccator bed. Once the nut
has fully withdrawn from the thread, the desiccator bed can be
removed from the assembly.
Lower Filters
12.15 To change the desiccator bed lower filter, proceed as follows:
i)
Invert the desiccator bed assembly and remove the spigot adapter,
leaving the threaded filter adapter bush complete with filter
attached to the bed.
ii)
The filter is a threaded fit in the brass filter adapter bush and can be
removed using a flat bladed screwdriver. Take care as the filter is made of
brittle material.
iii)
Fit a new filter, ensuring that it is tightened fully ’home’ and replace the
spigot adapter.
iv)
Re-invert the desiccator bed assembly.
Note
If any molecular sieve pellets inadvertently escaped, these should be replaced whilst
changing the upper filter.
Upper Filters
Note
The same care should be exercised as detailed for the lower filter.
12.16 To change the desiccator bed upper filter, proceed as follows:
i)
The desiccator bed should be removed as described under Para 12.14
ii)
Place the bed on its side to prevent the escape of molecular sieve
pellets and remove the spigot adapter revealing the filter, which can
be removed using a flat bladed screwdriver, leaving the filter adapter bush in
place in the desiccator bed.
iii)
Screw a new filter into the threaded bush, replace the spigot adapter into
the desiccator bed and tighten.
Note
If difficulty is experienced in refitting the assembly due to the molecular sieve,
gently tapping the desiccator bed will usually cause the pellets to settle. The
assembly should fit without further problems.
iv)
Return the desiccator bed to its upright position.
44
v)
Replace the desiccator bed by inserting it back through the banding
strips, ensuring that it mates with the union nuts. Tighten the nuts
finger tight and then refit the bed to the panel, tightening up the
lockscrews of each band. Finally ensure that the union nuts and
screws are securely tightened.
12.17 Repeat procedures as described in Paras 12.15 and 12.16 for the left hand desiccator
bed.
Changing the Solenoid Valve Cores
12.18 It is often expedient to replace the complete valve. However, to change the core of
the solenoid valve, proceed as follows:
i)
Ensure that the POWER OFF/ON switch is set OFF. Unlock and open the
hinged front door.
ii)
Pull on the ringpull of the safety relief valve fitted to the air receiver thus
causing it to de-pressurise. Hold it out until the RECEIVER gauge falls to
zero and then release. Disconnect the purge pipe connector
from the exhaust port of the solenoid valve.
iii)
Remove the securing nut from the end of the core tube. Take off the
washer and remove the solenoid coil.
iv)
Whilst holding the valve body with a suitable spanner, remove the core
tube assembly.
45
Fig 12 - Solenoid Valve Assembly
Caution
The core tube may be very tight. It is essential that the valve body be held securely
whilst the core tube is removed as the connecting pipework will otherwise be
damaged.
v)
Separate the core and spring from the core tube. Retain the core tube for
subsequent replacement.
vi)
Check that the core seating in the valve body and the core tube itself are
clean and undamaged; clean as necessary. Assemble the new core and
spring in the core tube and screw the assembly into position on the body.
Tighten securely, ensuring that the body is adequately supported.
vii)
Fit the solenoid coil, and washer onto the core tube. Fit and tighten the
securing nut and replace the purge pipe connector.
46
SERVICING THE NON-RETURN VALVE
12.19 To service the non-return valve, proceed as follows:
i)
Ensure that the POWER OFF/ON switch is set OFF. Unlock and open the
hinged front door.
ii)
Pull on the ringpull of the safety relief valve fitted to the air receiver thus
causing it to de-pressurise. Hold it out until the RECEIVER gauge falls to
zero and then release.
iii)
Remove the right hand desiccator bed as described under Para 12.14.
iv)
Slacken the union nut connecting the humidity sensing unit housing to the
non-return valve assembly. Support the regulating valve/humidity sensing
unit housing assembly whilst releasing the union nut.
v)
Release the left hand union nut of the reactivation orifice and the lefthand
connector nut of the non-return valve. The non-return valve assembly can
then be removed from the desiccator panel.
Fig 13 - Non-Return Valve Assembly
vi)
vii)
viii)
Undo the right hand connector nut of the non-return valve to enable
removal of the tee coupling attached to it.
Remove the right hand seat housing and withdraw the valve stem and spring.
Remove and discard the old sealing washer.
Clean the housing seat as necessary and re-assemble the valve using the
new components from the service kit. In order to ease re-assembly, insert a
screwdriver through the seat housing nut to hold the valve stem in the body
whilst tightening the nut.
47
Caution
If resistance is felt as the nut is tightened, the stem is not correctly located in the
valve body. Remove the nut and re-commence assembly as the valve stem can be
easily damaged.
xi)
Repeat steps vii) and viii) for the left hand section of the valve.
Note
Section 12.19 details only the right hand section of the valve. The left side is
however identical in all respects.
xii)
Assembly is a reversal of the process described under iii) to vi)
xi)
Check the assembly for leaks as described in Para 12.4.
CHANGING THE REACTIVATION ORIFICE
12.20 To change the reactivation orifice, proceed as follows:
i)
Ensure that the POWER OFF/ON switch is set to OFF. Unlock and
open the hinged front door.
ii)
Undo the pipe connector nuts of the tee couplings in the upper branch of the
desiccator assembly and remove the copper tubing branch complete with
reactivation orifice.
iii)
Use a spanner to disconnect the two pipe connector nuts on the
reactivation orifice, using a second spanner to hold the component.
iv)
Carefully locate the two copper tubing pieces into the new reactivation
orifice and tighten the two pipe connector nuts.
v)
Replace this assembly into the tee couplings in the upper branch of the
desiccator and tighten the union nuts.
vi)
Check the purge flowrate as described in Para 12.7.
48
SECTION 13 - DIAGNOSTICS
INTRODUCTION
13.1
In the event that a fault occurs on the equipment, reference should first be made to
Table 3. Having diagnosed the malfunction, refer to the relevant text as indicated in
the ‘Remedy’ column of Table 3.
Notes
1)
In some cases a cross reference is not given in the ‘Remedy’ column if the
work requires no specialist knowledge, e.g. - changing a fuse.
2)
The diagnosis given in Table 3 is obviously not fully exhaustive, but details
the common faults which practical experience has shown to occur most
often. If the information in this table does not help cure the fault, reference
should be made to the electrical circuit diagram Fig. 5 or the pneumatic
diagram Fig. 8.
TABLE 3 - MALFUNCTION DIAGNOSIS
SYMPTOMS
Relevant lamp does not light
when circuit check (wet or
dry) pressed.
Compressor runs
continually
POSSIBLE FAULT
a) Lamp failed
a) Replace lamp
(see Para. 11.2)
b) Faulty printed circuit board
b) Test board using
Tester Humidity 1A
(see Para. 12.12)
a) Replace switch
(see Para 14.7)
a) Contacts of compressor pressure switch permanently closed.
b) Unit undersized
Receiver gauge never rises
above zero although
compressor operates
normally.
Unit continuously gives
NOT FILLING WET
indication.
REMEDY
a) Minimum pressure regulating
valve setting incorrect.
b) Check total cable
flow (see Paras 3.2-3.4)
a) Adjust valve setting
(see Para 14.9)
b) Receiver relief valve faulty.
b) Replace receiver
safety relief valve (see
Para 14.10)
c) Non-return valve faulty
c) Service non-return
valve (see Para 12.19)
d) ‘Dump’ solenoid permanently
open to atmosphere
d) Check the humidity
detector system (see
Para 12.10)
a) Unblock or replace
reactivation orifice (see
Para 12.20)..
a) Reactivation orifice blocked or
restricted. Check purge with
flowmeter.
49
Unit does not run and
POWER lamp not lit
Mains Fail external alarm
activated
‘Running Hours’ meter does
not revolve when
compressor running.
Compressor cuts in and/or
out at wrong pressure
Outlet flowrate low or
decreasing markedly
b) Sensing element faulty.
b) Replace as
necessary.
c) Non-return valve faulty.
c) Service non-return
valve (see Para 12.19)
d) Faulty process timer
d) Replace as necessary
e) Bed changeover solenoid
faulty.
e) Repair/replace valve
(see Para 12.18)
f) Desiccator bed filter(s)
blocked.
f) Replace filters (see
Para 12.13 - 12.17).
g) Faulty printed wiring board.
g) Check the humidity
detector system (see
Para. 12.10)
a) Connect to supply
a) Unit not connected to mains
supply
b) Mains supply failed
b) Investigate supply
problem
c) Fuse blown
c) Replace fuse (see
Para 14.2)
d) Power switch faulty
d) Replace power
switch (see Para 14.11)
a) Check wiring (see
Para 12.9)
a) Damaged wiring
b) Meter faulty
b) Replace meter (see
Para 14.6)
a) Compressor pressure switch
requires adjustment
a) Adjust switch (see
Para 14.8)
b) Compressor pressure switch
faulty
b) Replace switch (see
Para 14.7)
a) Desiccator bed filter(s)
blocked
a) Change filters (see
Paras 12.13 - 12.17)
b) Compressor worn or faulty.
b) Replace compressor
(see Para 14.3)
50
Fan running but compressor
not cutting in,
FILLING/DRY lamp lit
FILLING/DRY lamp lit but
compressor cooling fan not
running
FILLING/DRY lamp lit,
compressor running but fan
not running
Unit runs normally but
neither FILLING/DRY nor
NOT FILLING/WET lamps
light when CIRCUIT
CHECK button depressed
c) Compressor filter blocked.
c) Replace filter (see
Para 11.3)
d) Internal Pipework leaking
d) Check for leaks and
repair as necessary
(See Para 12.4)
a) Replace compressor
(see Para 14.3)
a) Compressor faulty
a) Compressor control pressure
switch faulty
a) Replace switch
(see Para 14.7)
a) Fan burnt out or faulty
a) Replace fan
(See Para 14.4)
a) Lamp failed
a) Replace lamp
(See Para 11.2)
b) Printed circuit board fuse
blown
b) Replace on-board
fuse (See Para 14.2)
c) Printed circuit board faulty
c) Test pcb using
Tester Humidity 1A
(See Para 12.12).
51
SECTION 14 - REPAIRS
INTRODUCTION
14.1
This section is for use in conjunction with Section 13 which covers fault diagnosis.
However, rather than unnecessary duplicate information under this heading, details
of how to carry out several ‘repairs’ which also fall into the ‘maintenance’ category
can be found in the preceding sections referred to in Table 3.
Fuse Replacement
NOTE
Two fuses are used within the equipment. One is situated within the mains plug, the
other fitted to the Humidity Detector printed circuit board. It is essential that the
correct value fuse be fitted as a replacement as follows:
Mains Plug
Printed Circuit Board
14.2
13A QB
250mA AS
Ceramic Quick Blow 1¼“
Anti Surge 20 mm
If it is necessary to replace a blown printed circuit board fuse, proceed as follows:
i)
Set the POWER OFF/ON switch to OFF
ii)
Open the hinged front door.
iii)
Remove the four screws securing the printed circuit board cover to enable
access to the board itself.
iv)
Withdraw the suspect fuse from its holder and test using a suitable
instrument such as a multimeter. If the fuse has blown, proceed from Step
v) below.
v)
Ensure that the fuse clips are clean and undamaged. Clean and carefully
bend them to improve contact if necessary.
vi)
Fit the fuse in the holder
vii)
Refit the printed circuit board cover, close the door and set the POWER
OFF/ON switch to ON.
viii)
Carry out a system test. If the fuse immediately blows again, further fault
diagnosis must be carried out and the fault repaired before fitting another
fuse.
52
Fig 14 - Compressor Removal
Compressor Replacement
14.3
In the event that the compressor requires replacement, proceed as follows:
i)
Set the POWER OFF/ON switch to OFF.
ii)
Unlock and open the hinged front door.
iii)
Disconnect the electrical lead from the compressor. The terminal cover is
removed by loosening the two hexagon headed screws at the left hand end
of the compressor. Note the position of the crimp terminal connections
before disconnecting as you will require this information to enable
replacement.
iv)
Disconnect the braided outlet hose at the union on the head of the
compressor.
v)
Undo and remove the two hexagon headed bolts securing the compressor
support plate to the air receiver.
vi)
Carefully withdraw the compressor assembly complete with its mounting and
support plates.
53
vii)
Place the compressor on its side and remove the four hexagon headed bolts
securing the compressor to its mounting plate. The anti-vibration mountings
need not be disturbed.
viii)
Correctly position the replacement compressor on the mounting plate and
secure with the four hexagon headed bolts.
ix)
Remove the union from the head of the defective compressor and fit to the
replacement compressor together with the intake filter assembly. Use PTFE
tape on the threads.
x)
Re-position the compressor complete with mounting and support plates onto
the air receiver and secure with the two hexagon headed bolts removed in v).
xi)
Connect the compressor lead and replace the terminal cover.
xii)
Re-connect the braided outlet hose to the union fitted to the compressor
head.
xii)
Close and lock the hinged front door.
xiv)
Set the POWER OFF/ON switch to ON.
Fan Replacement
14.4
If the fan should need replacement, proceed as follows:
I)
Switch the POWER OFF at the wall socket outlet.
ii)
Open the hinged front door.
iii)
Disconnect the three wires from the terminals on the fan assembly,
marking the wires carefully for subsequent reconnection.
iv)
The fan and grille are fitted to the inside top face of the cabinet. Remove the
four screws, nuts and washers and withdraw the fan and grille, noting the
orientation.
v)
Fit the new fan in position with the air flow arrow pointing uppermost
and the grille underneath it. Secure with the four screws, nuts and washers.
vi)
Reconnect the three wires to the corresponding fan terminals.
vii)
Close and re-secure the hinged front door. Set the power ON at the
wall socket outlet.
54
Pressure Gauge Replacement
14.5
In the event that either of the pressure gauges require replacement, proceed as
follows:
i)
Set the POWER OFF/ON switch to OFF.
ii)
Open the hinged front door.
iii)
Pull on the ringpull of the safety valve fitted to the air receiver thus causing
it to de-pressurise. Hold it out until the RECEIVER gauge falls to zero and
no more air can be heard escaping, then release.
iv)
If the RECEIVER gauge is being replaced, release the union nut securing the
cross coupling to the pipe fitting at the rear of the gauge. If the
COMPRESSOR gauge is being replaced, loosen the pipe nut at the rear of
the gauge and withdraw the tubing itself from the fitting.
v)
Remove the pipe fitting from the rear of the gauge, holding the gauge to
prevent it from rotating. In the case of the RECEIVER gauge, release the
securing nut and bridge piece and withdraw the gauge through the front of
the door panel. The clamp fixing the COMPRESSOR gauge is released by
slackening the e two slotted screws fixed through the clamp at either end.
vi)
Check that the replacement gauge to be fitted is of the correct type. The
RECEIVER gauge is of 0 - 160 psi range, whilst the COMPRESSOR gauge
is 0 - 150 psi, and liquid filled.
vii)
Fit the new gauge in the panel cutout and position the bridge piece behind.
Secure this with the backnut in the case of the RECEIVER gauge, or by
tightening the two slotted screws of the COMPRESSOR gauge. Refit the
union and secure all remaining couplings and tubing removed during steps
iv) - v) above.
viii
Close the hinged front door and set the POWER OFF/ON switch to ON.
Running Hours Meter Replacement
14.6
In the event that the ‘Running Hours’ meter requires replacement, proceed as
follows:
i)
Switch the POWER OFF at the wall socket outlet.
ii)
Open the hinged front.
iii)
Disconnect the wires from the terminals at the rear of the meter, noting
their respective positions for subsequent replacement.
iv)
Press the plastic clips on either side of the meter inwards and push it
through the panel. Remove the meter.
55
v)
Push the replacement meter into position and reconnect the wires.
vi)
Close the hinged front door.
vii)
Set the POWER OFF/ON switch to ON.
Compressor Control Pressure Switch Replacement
14.7
If the compressor control pressure switch requires replacement, proceed as
follows:
i)
Switch the POWER OFF at the wall socket outlet.
ii)
Open the hinged front door.
iii)
Pull on the ringpull of the safety valve fitted to the air receiver thus causing
it to de-pressurise. Hold it out until the RECEIVER gauge falls to zero and
then release.
iv)
Slacken the two screws on top of the compressor control pressure
switch and remove the front cover.
Fig 15 - Compressor Control Pressure Switch
56
v)
Disconnect the wires from their internal terminal block, noting their
positions for subsequent reconnection. Withdraw the cables carefully
through the grommet.
vi)
Disconnect the fitting from the pressure port on the base of the
pressure switch.
vii)
Remove the two screws securing the unit to the inner door panel.
viii)
Tighten the fitting (using PTFE tape) on the pressure port. Do not overtighten.
ix)
Position the replacement pressure switch and fit and tighten the securing
screws.
x)
Pierce a suitable hole through the grommet and carefully thread the wires
through into the unit. Connect the wires to the correct terminals on the
terminal block.
xi)
Slide the plastic cover onto the pressure switch and tighten the two retaining
screws.
xii)
Adjust the pressure settings as detailed in Para 14.8
Compressor Control Pressure Switch Adjustment
14.8
To adjust the pressure switch settings, proceed as follows:i)
Set the POWER OFF/ON switch to OFF.
ii)
Unlock and open the hinged front door.
WARNING
THE AIR RECEIVER AND ASSOCIATED FITTINGS AND TUBING ARE
NOW PRESSURISED AT UP TO 100 PSI. CAUTION SHOULD BE
EXERCISED WHILST CARRYING OUT THE FOLLOWING.
iii)
Pull on the ringpull of the safety valve fitted to the air receiver thus causing
it to de-pressurise. Hold it out until the RECEIVER gauge falls to zero then
release.
iv)
Turn the left hand square on top of the pressure switch until the START
range scale reads 4.5 Bar.
v)
Turn the right hand hexagon on the top of the pressure switch until the
DIFF range reads 2.3 Bar.
vi)
Switch on the unit and check the pressure at which the compressor
cuts out. This should be 65 psi (4.5 Bar). To alter this setting, repeat steps
i) to iii) above and adjust the left hand square on top of the pressure
switch as necessary.
57
Note
Although labelled START, the left hand range shows the pressure at which the compressor
stops. This setting must always be adjusted accurately before adjusting the DIFF scale.
The DIFF scale indicates the difference between start and stop pressures, not the start
pressure itself.
vii)
When the required setting has been achieved, reduce air
pressure in the receiver by pulling the pullring such that the
safety relief valve just opens. Observe the RECEIVER gauge,
which should indicate 32 psi (2.2 Bar) when the compressor re-starts.
If necessary, adjust the right hand hexagon on top of the pressure
switch.
viii)
With both the cut-out pressures correctly set, close and lock the
front door of the CDU 3C.
Minimum Pressure Regulating Valve Adjustment
14.9
To maintain drying efficiency, the back pressure of the desiccator is set at 4.3 Bar.
This can be checked and adjusted as follows:
i)
Set the POWER OFF/ON switch to ON. If the compressor does not
start, discharge the air receiver by using the safety relief valve.
ii)
The COMPRESSOR gauge should rise to 62 psi (4.3 Bar) at which point air
will begin to enter the air receiver. The receiver gauge can be seen to rise at
this point. If, however, this requires adjustment, alter the setting of the
minimum pressure regulating valve.
iii)
Slacken the locknut of the adjusting screw, which should be turned clockwise
to increase pressure. After adjustment, re-tighten the locknut and check the
gauge readings.
Air Receiver Safety Relief Valve Replacement
14.10 The safety relief valve is set to open at 102 psi (7.0 Bar). It is factory set and
should not require adjustment. If however, during the routine checking for leaks, it
is found that this valve does leak, it is likely to be worn seat necessitating
replacement. This should be carried out as follows:
i)
Set the POWER OFF/ON switch to OFF.
ii)
Unlock and open the hinged front door.
iii)
Pull on the ringpull of the safety valve fitted to the air receiver thus causing
it to de-pressurise. Hold it out until the RECEIVER gauge falls to zero then
release.
58
WARNING
UNDER NO CIRCUMSTANCES MUST ANY ATTEMPT BE MADE TO
REMOVE THE RELIEF VALVE UNTIL THE RECEIVER IS COMPLETELY
DEPRESSURISED.
iv)
Fit the new relief valve, using 3 or 4 turns of PTFE tape on the pipe
thread before fitting.
Caution
Do not over-tighten the relief valve; the air receiver has to be returned to the
manufacturer for replacement of a damaged socket.
vi)
Set the POWER OFF/ON switch to ON and when the air receiver has
become pressurised, perform a leak test around the area of the relief
valve using a suitable detecting solution. Tighten the valve further if
necessary.
Power Off/On Rocker Switch Replacement.
14.11 The POWER OFF/ON rocker is rated at 10A and is combined with a neon
indicator. The unit is replaced as an assembly as follows:
i)
Disconnect the CDU 3C from the mains power source at the socket
outlet.
ii)
Open the control hinged front door.
iii)
Pull back the shrouded terminal cover to allow access to the connectors and
remove the connectors from the rear of the switch, noting their respective
positions for subsequent replacement.
iv)
Press the plastic clips at the top and bottom rear of the switch to release and
withdraw the assembly through the front of the panel.
v)
Push the new switch assembly through the front of the control panel,
ensuring that the clips are fully engaged at the rear.
vi)
Reconnect the wires, and close the hinged front door.
vii)
Reconnect power at the socket outlet and set the POWER OFF/ON switch to
ON to verify correct operation.
59
SECTION 14 SPARES PARTS
All spares can be obtained from the manufacturer. Please contact the sales or service
department at the following address:
DRALLIM TELECOM
MILLWOOD HOUSE, DRURY LANE, PONSWOOD INDUSTRIAL ESTATE,
ST. LEONARDS ON SEA, EAST SUSSEX TN38 9BA
Telephone 01424 205140
Fax 01424 202140
Product development may change details and specifications.
TABLE 4 - SPARE PARTS
ITEM
Compressor
Compressor
Safety Relief Valve
Flexible Compressor
Hose
Compressor Pressure
Gauge
Receiver Pressure
Gauge
Solenoid Valve 3 way
Desiccator Changeover
(High Humidity By
Pass)
Solenoid Valve 2 way
Element Check
Reactivation Orifice
Non Return Valve
Service Kit *1
Non
Return
Valve
Complete
Solenoid Valve Service
Kit (Core)
Solenoid Valve Service
Kit (Core)
Humidity Sensing
CIRCUIT
REF
-
MANUFACTURER
DRALLIM
(PT. NO)
PART NO.
GAST
(71R142
- 6500240
POO1B - D301X)
GAST (AF592S)
6520450
-
DRALLIM
13629/2
PG 2
WIKA (213.53.063)
1300496
PG 1
WIKA (111.12.063)
1300528
SV1, SV2, SV3
PARKER LUCIFER
(131 M14)
1805569
SV4
1805525
NRV
PARKER LUCIFER
(121 M13)
DRALLIM
DRALLIM
SK303/CP/GW
1410474
NRV
DRALLIM
13671/S/B
PARKER LUCIFER
(488877)
PARKER LUCIFER
(488878)
OHMIC (HS - 1)
1606271
SV1, SV2, SV3
SV4
HS
60
1606270
1210264
ITEM
Element *2
Humidity Detector
Printed Circuit Board
Pressure Maintaining
Valve
Compressor Control
Pressure Switch
Low Output Pressure
Switch
Air Receiver Safety
Relief Valve
On-Off
Circuit Breaker
Fan
CIRCUIT
REF
MANUFACTURER
(PT. NO)
HD
DRALLIM
PMV
IMI NORGREN
(V06-222-NNKD)
DANFOSS (KP35)
PSW 1
PSW 2
SUCO
0180 45803 1 006
BAMBI
COMPRESSORS
ETA
(3120-F451)
ZIEHL - EBM
(W25S107-AA01-40)
OMRON
(G2R-2 230VAC)
CROUZET
(88-611-3)
CURTIS
INSTRUMENTS
ARCOLECTRIC
(CO911NB/BLACK/
BLACK)
CBR
-
Mains Fail Relay
Low Output Relay
Process Timer
RLA
RLB
PT1
Running Hours Meter
HCR
Element Check
Pushbutton Switch
Override
Pushbutton Switch
Dry Circuit check
Pushbutton Switch
SW1
Wet Circuit Check
Pushbutton Switch
SW3
Running Command
Lamp & Holder
Filling Lamp
(LED Cluster)
Not Filling Lamp
(LED Cluster)
Filling Lamp
Lampholder
Not Filling Lamp
Lampholder
Dry Air Outlet
Plug (Quick Release
Desiccant
Molecular Sieve
Desiccator Bed
Filter
SW4
SW2
DRALLIM
PART NO.
13970/110AC/
240AC
1805396
1706636
1706568
1805264
1705874
1122570
1626260
1715628
1122868
1707076
LP1
ARCOLECTRIC
(CO911NB/BLACK/
GREEN)
ARCOLECTRIC
(CO911NB/BLACK/
RED)
ARCOLECTRIC
1425675
LP2
RS (585-668)
1425474
LP3
RS (585-652)
1425473
LP2
ARCOLECTRIC
(T0063/AO/GREEN)
ARCOLECTRIC
(T0063/AO/RED)
A.V.S.
(5350 - 1/8)
LAPORTE
(4A-8/2 2.5 - 5mm)
PORVAIR
(AEL1050/B30
1425677
LP3
61
1707077
1707078
1425676
1123006
1205033
1225501
ITEM
Solenoid Valve
Exhaust Fitting
Fuse (20 mm)
Humidity Detector
Board 250mA A/S
Compressor
Anti-Vibration Mount
Air Receiver
Drain Valve
“O” Ring Sensing
Element Cover
“O” Ring Desiccator
Bed Filter Adaptor
Compressor Filter *3
CIRCUIT
REF
SV1, SV2, SV3
F1
MANUFACTURER
(PT. NO)
MICROPLASTICS
(011032 FB 12N)
-
DRALLIM
PART NO.
1225450
AVA LTD (AVM191)
1500862
VALVESTOCK (33)
4300020
DOWTY
200-021-7770
DOWTY
200-112-4490
GAST (B344A)
6520650
3956002
NOTES
The following items can be obtained through BT Central Stores:*1
Kit Repair 10A
Item code 072077
*2
Element Humidity Sensing
Item code 310945
*3
Filter Compressor 1A
Item Code 072490
DOCUMENT ISSUE
ISSUE
01
02
03
04
05
06
DATE
21 July 2000
02 July 2001
22 October 2001
10 January 2003
26 August 2009
62
RFD/DCR
DCR T4942
DCR T4975
DCR T5195
DCR T6329