Trouble Shooting Of Refrigerant Cycle - Fujitsu ASU9RLQ Service Instructions Manual

Trouble Shooting of Refrigerant Cycle

[Diagnosis Table for Defective Component]
: Item of most possible cause
Refrigerant leak
Compressor failure(*)
EEV failure (*)
Thermistor failure (*)
(*) Trouble Shooting Method
(1) Checking method of the compressor failure
Insert the AC plug and start up the cooling operation. Input Test operation signal and check if the
compressor operates.
If it does not operate, measure the resistance value of compressor windings between U-V, V-W,
W-U.
If any of the resistance value between U-V, V-W, W-U is not same as others, the compressor is
defective.
Compressor Failure
ASU9/12RLQ
ASU18CL/RL
(The above resistance value is a typical value. There is some distribution. A
compressor temperature, the measured value may be much different from the above table when
measured right after stopping operation.)
(2) Checking method of EEV failure
- Insert the AC plug and start up the operation. Check if the EEV operates just before compressor is turned
on. (Touch EEV by hand and check it.)
If it does not operate, check if the coil or connector of EEV is removed or loose.
If it operates, check the discharge thermistor / outdoor heat exchanger thermistor / indoor heat
exchanger thermistor. (Refer to (3) for checking method.)
(3) Checking method of Thermistor
- Check each thermistor if it is removed or the connector is loose.
If there is no problem, remove the connector of the thermistor from the PCB and check the resistance
value (refer to the thermitor characteristics table).
Compressor
IPM Protection
Location error
Compressor Case Temperature at 68°F(20°C): 0.710 ohm
Compressor Case Temperature at 68°F(20°C): 0.730 ohm
Discharge
Temperature Error
NORMAL
s it also changes by the
07-09
Cooling High
Pressure
Protection