Troubleshooting SiBE07-618_C90 Service Diagnosis4.23 Refrigerant ShortageRemoteControllerDisplayU0Method ofMalfunctionDetectionRefrigerant shortage detection I:Refrigerant shortage is detected by checking the input current value and the compressor outputfrequency. If the refrigerant is short, the input current is smaller than the normal value.Refrigerant shortage detection II:Refrigerant shortage is detected by checking the discharge pipe temperature and the opening ofthe electronic expansion valve. If the refrigerant is short, the discharge pipe temperature tendsto rise.MalfunctionDecisionConditionsRefrigerant shortage detection I:The following conditions continue for 7 minutes. DC current ≤ × Output frequency + Output frequency >Refrigerant shortage detection II:The following conditions continue for 80 seconds. Target opening of the electronic expansion valve ≥ Discharge pipe temperature > × target 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 errorSupposedCauses Disconnection of the 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) (Hz)18/1000 0.7 55(pulse) (–) (°C)50 class 480 128/128 Cooling: 20, Heating: 4560 class 480 128/128 Cooling: 60, Heating: 45
