Fujitsu AO*12LFBC, Service Instructions Manual

Page: 60 / 83

Trouble Shooting of Refrigerant Cycle
[Diagnosis Table for Defective Component]
: Item of most possible cause
IPM Protection
Compressor
Location error
Discharge
Temperature Error
Cooling High
Pressure
Protection
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
NORMAL
ASY9/12LSACW Compressor Case Temperature at 25degC: 0.512 ohm
ASY9/12LSBCW Compressor Case Temperature at 20degC: 0.701 ohm
ASY14/18LSBCW Compressor Case Temperature at 25degC: 0.730 ohm
(The above resistance value is a typical value. There is some distribution. As it also changes by the
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).
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