Refrigerant Shortage - Daikin CTXU25G2V1B Service Manual

SiBE12-908

2.31 Refrigerant Shortage

U0
Remote
Controller Display
Method of Refrigerant shortage detection I:
Refrigerant shortage is detected by checking the input current value and the compressor
Malfunction
running frequency. If the refrigerant is short, the input current is smaller than the normal value.
Detection
Refrigerant shortage detection II:
Refrigerant shortage is detected by checking the discharge pipe temperature and the opening of
the electronic expansion valve. If the refrigerant is short, the discharge pipe temperature tends
to rise.
Malfunction Refrigerant shortage detection I:
40 class
Decision
The following conditions continue for 7 minutes.
Conditions
50 class
The following conditions continue for 7 minutes.
Refrigerant shortage detection II:
The following conditions continue for 80 seconds.
If a refrigerant shortage error takes place 4 times successively, the system is shut down. The
error counter resets itself if this or any other error does not occur during the following 60-minute
compressor running time (total time).
Supposed
Causes
Service Diagnosis
Input current × input voltage
Output frequency > 51 (Hz)
Input current × input voltage
Output frequency > 48 (Hz)
Target opening of the electronic expansion valve ≥ 450 (pulse)
Discharge pipe temperature > 128 / 128 × target discharge pipe temperature +20 (°C)
Refrigerant shortage (refrigerant leakage)
Refrigerant heat exchanger drift
Poor compression performance of compressor
Closed stop valve
Defective electronic expansion valve
≤
2111 / 256 × output frequency – 361 (W)
≤
4628 / 256 × output frequency – 608 (W)
Troubleshooting
154