Refrigerant Shortage - Daikin FTXN25KEV1B Service Manual

SiBE041102_A

4.22 Refrigerant Shortage

U0
Remote
Controller
Display
Method of Refrigerant shortage detection I:
Malfunction Refrigerant shortage is detected by checking the input current value and the compressor
running frequency. If the refrigerant is short, the input current is lower 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:
Decision The following conditions continue for 7 minutes.
Conditions
Refrigerant shortage detection II:
The following conditions continue for 80 seconds.
Supposed
Causes
Service Diagnosis
Input current × input voltage
Output frequency > C
(W)
A (–) B
1600/256 –160
Opening of the electronic expansion valve ≥ D
Discharge pipe temperature > E × target discharge pipe temperature + F
Cooling
25 class
Heating
Cooling
35 class
Heating
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 60 minutes without any other error
Disconnection of discharge pipe thermistor, indoor or outdoor heat exchanger thermistor,
room or outdoor temperature thermistor
Closed stop valve
Refrigerant shortage (refrigerant leakage)
Poor compression performance of compressor
Defective electronic expansion valve
≤
A × output frequency + B
(Hz)
C
46
(pulse) E
D
190/128
470
211/128
160/128
470
172/128
Troubleshooting
(°C)
(–) F
–7
–11
–1.5
–8
83