Service Manual

Troubleshooting SiUS04-921
132 Service Diagnosis
2.30 Insufficient Gas
Remote
Controller Display
U0
Outdoor Unit LED
Display
A5 55 ( - )
Method of
Malfunction
Detection
Gas shortage detection I:
Gas shortage is detected by checking the input current value and the compressor running
frequency. If the gas is short, the input current is smaller than the normal value.
Gas shortage detection III:
Gas shortage is detected by checking the difference between ambient temperature and heat
exchanger temperature. If the gas is short, the difference is smaller than the normal value.
Malfunction
Decision
Conditions
Gas shortage detection I:
The following conditions continue for 7 minutes.
 Input current × input voltage
≤ 2800 / 256 × output frequency –350 (W)
 Output frequency > 54 (Hz)
Gas shortage detection III:
When the difference of the temperature is smaller than , it is regarded as insufficient gas.
If a gas shortage error takes place 4 times straight, the system will be shut down. The error counter
will reset itself if this or any other error does not occur during the following 60-minute compressor
running time (total time).
Supposed
Causes
 Refrigerant shortage (refrigerant leakage)
 Refrigerant heat exchanger drift
 Poor compression performance of compressor
 Closed stop valve
 Defective electronic expansion valve
 Defective solenoid valve for dehumidifying
Cooling
room temperature
− indoor heat exchanger temperature 4.0°C (7.2°F)
outdoor heat exchanger temperature
− outdoor temperature 4.0°C (7.2°F)
Heating
indoor heat exchanger temperature
− room temperature 4.0°C (7.2°F)
outdoor temperature
− outdoor heat exchanger temperature 4.0°C (7.2°F)