Refrigerant Shortage - Daikin SiENBE07-618_C Service Manual

Troubleshooting

4.23 Refrigerant Shortage

U0
Remote Control
Display
Method of Refrigerant shortage detection I:
Malfunction Refrigerant shortage is detected by checking the input current value and the compressor output
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:
The following conditions continue for 7 minutes.
Decision
Š DC current ≤
Conditions
Š Output frequency >
Refrigerant shortage detection II:
The following conditions continue for 80 seconds.
Š Target opening of the electronic expansion valve ≥
Š Discharge pipe temperature >
„ If the error repeats 4 times, the system is shut down.
„ Reset condition: Continuous run for about 60 minutes without any other error
„ Disconnection of the discharge pipe thermistor, indoor or outdoor heat exchanger thermistor,
Supposed
Causes
„ Closed stop valve
„ Refrigerant shortage (refrigerant leakage)
„ Poor compression performance of compressor
„ Defective electronic expansion valve
90
× Output frequency +
(–) (A)
18/1000 0.7
(pulse)
50 class 480
60 class 480
room or outdoor temperature thermistor
(Hz)
55
× target discharge pipe temperature +
(–) (°C)
128/128 Cooling: 20, Heating: 45
128/128 Cooling: 60, Heating: 45
SiENBE07-618_C
Service Diagnosis