Insufficient Gas - Daikin E-Series Service Manual

SiENBE12-620

5.25 Insufficient Gas

U0
remote control
Display
Outdoor Unit LED
A
Display
Method of
Gas shortage detection I:
Malfunction
Gas shortage is detected by checking the input current value and the compressor running
Detection
frequency. If the gas is short, the input current is smaller than the normal value.
Gas shortage detection II:
Gas shortage is detected by checking the discharge temperature and the opening of the
electronic expansion valve. If the gas is short, the discharge temperature tends to rise.
Malfunction
Gas shortage detection I (typical value):
Decision
The following conditions continue for 7 minutes.
Conditions
Gas shortage detection II:
The following conditions continue for 80 seconds.
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
Service Diagnosis
U0
1 2 3 4
5 1 1 4
DC current ≤ 0.01 × output frequency + 0.3
Output frequency > 55 (Hz)
Target opening of the electronic expansion valve ≥ 450 (pulse)
Cooling: discharge temperature > 255 / 256 × target discharge temperature +20 (°C)
Heating: discharge temperature > 255 / 256 × target discharge temperature +40 (°C)
Refrigerant shortage (refrigerant leakage)
Poor compression performance of compressor
Discharge pipe thermistor disconnected, or indoor unit or outdoor unit heat exchanger
thermistor disconnected, room or outside air temperature thermistor disconnected
Stop valve closed
Electronic expansion valve defective
4
Troubleshooting
247