10 - 1
Air Conditioning
Procedures that require charging or discharging the system are not given in this manual as they require special equipment that
is usually held only by trained refrigeration engineers.
The system will not function in very low ambient temperatures, therefore tests should be carried out in a warm environment.
It is recommended that, to locate faults on the system accurately and quickly, an electronic leak detector and a refrigerant
pressure gauge should be used. However, leaks can be detected on the system by using soapy water applied to the
suspected leak area and system pressure can be assessed by the state of refrigerant passing through the receiver drier sight
glass. Following sections of the manual deal with the major components of the air conditioning systems and give further fault
finding and maintenance information.
General Fault Indications
There are several indications that may help to determine the fault area on a system not working efficiently:
a) Poor performance Low system pressure - Evacuate and recharge system.
Condenser coil air flow restricted - Remove debris from around coil using
compressed air or low pressure water.
b) Warm or slightly cool air Expansion valve stuck open or closed - Renew expansion valve.
emitted from unit
c) Blower operates on fan Blower resistor failed - Renew resistor.
speed 3 only Blower motor failed - Renew blower motor.
d) Compressor clutch Condenser coil blockage - Remove debris from around coil/renew
condenser.
continually cuts out Overcharging of refrigerant system- Evacuate and recharge system.
Blocked expansion valve/condenser - Clear blocked component .
Sight Glass Indications
An approximate indication of the condition of the refrigerant can be seen through the receiver/drier sight glass when the
compressor is running. Refer also to Service Procedures - Checking Refrigerant Charge Level.
Clear - No fault indicated unless the system is unable to provide cool air. The indication then is that
the system is completely discharged of refrigerant.
Foam or bubbles - Refrigerant low and in need of charging.
Clouded - Dessicant breakdown in the receiver-drier.
Note: Sight glass indications cannot always give a positive identification of a problem. Further diagnosis, preferably by a
refrigeration engineer using pressure gauges, is advisable before reaching a definite conclusion.
Section B Body & Framework
9803/7130
Section B
10 - 1
Issue 1
Fault Finding
S201520
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