962 / 1006
HVAC
853
HVAC
REFRIGERATING CYCLE TROUBLE-
SHOOTING
1. INSUFFICIENTREFRIGERANT
Condition
•
Air conditioner does not cool effectively
Symptoms in refrigerant cycle
•
Pressure on both the high and low pressure
sides is low
•
Air around the air outlet is slightly cold
Cause
•
There is gas leakage in the refrigerating cycle
Diagnosis
•
Insufficient refrigerant in the refrigerating cycle
•
Refrigerant leakage
Countermeasures
•
Locate the leaking and repair
•
Recharge refrigerant to the specified amount
2. EXCESSIVE REFRIGERANT OR INSUFFICIENT
CONDENSER COOLING
Condition
•
Air conditioner does not cool effectively
Symptoms in refrigerant cycle
•
Pressure on both the high and low pressure
sides is high.
Cause
•
Refrigerant is overcharge in the refrigerating cycle,
causing poor cooling performance.
•
Condenser cooling performance is poor
•
Fluid coupling on fan is slipping
Diagnosis
•
Excessive refrigerant in the refrigerating cycle
•
Overcharged refrigerant
•
Poor condenser cooling performance
•
Condenser fins blocked or fan belt loose
•
Slipping radiator fan fluid coupling
•
Silicone oil leaking from the coupling
Countermeasures
•
Clean the condenser
•
Tighten the AC belt to the correct tension
3. ENTRY OF MOISTURE IN THE REFRIGERANT
CYCLE
Condition
•
Air conditioner alternately cools and does not
cool
Symptoms in refrigerant cycle
•
During operation, the pressure on the low pressure
side alternates between vacuumand normal
Cause
•
The moisture mixed in the refrigerant in the
refrigerating cycle freezes in the expansion valve
orifice, blocking the cycle. After a time, the ice
melts and normal conditions return
Diagnosis
•
The drier is in an oversaturated condition
•
The moisture in the refrigerating cycle freezes
the expansion valve orifice, impeding refrigerant
circulation
Countermeasures
•
Remove the moisture by repeated evacuation
•
Recharge new refrigerant to the specified amount
4. REFRIGERANT FAILSTOCIRCULATE
Condition
•
Air conditioner does not cool
Symptoms in refrigerant cycle
•
Pressure on the low pressure side is vacuum
and pressure on the high pressure side is
extremely low
•
Frost or dew is formed on the piping at the front
and rear side of the receiver or the expansion
valve
Cause
•
Moisture or dirt in the refrigerating cycle freezes or
sticks to the expansion valve orifice, obstructing
refrigerant flow.
•
Gas leaking from the heat sensitizing tube of the
expansion valve obstructs refrigerant flow
Diagnosis
•
Blocked expansion valve orifice
Countermeasures
•
Allow to stand for some time and then resume
operation to decide whether the blockage is caused
bymoisture or by dirt. If caused bymoisture; remove