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37
Troubleshooting
Troubleshooting Guidelines
Error Codes
Error Description
Action
0
Normal
No action.
U0
Insuf
fi
cient gas
1. Check sensor connection.
2. Check stop valve.
3. Check for gas leak.
4. Check the EXV.
5. Check H8.
U2
DC voltage out of range
1. Check the supply voltage.
2. Check the outdoor fan by rotating with hand.
3. Restart the system.
4. Check power supply waveform.
U4
Communication error
1. Check the indoor unit - outdoor unit connection wires.
2. Check the voltage of the signal terminal.
3. Check the indoor fan by rotating with hand.
4. Check the power supply waveform.
UA
Installation error
1. Check the indoor and outdoor unit model name.
2. Check the part code on the indoor and outdoor PCB.
A1
Indoor PCB error
1. Check connector connection.
2. Replace indoor PCB.
A5
Antifreeze
1. Check the air passage.
2. Check the intake air
fi
lter.
3. Check dust accumulation on indoor coil.
4. Check wiring and piping.
5. Check the EXV.
6. Check indoor coil sensor resistance value.
7. Check refrigerant level.
8. Check room sensor resistance value.
A6
Indoor fan motor abnormal
1. Check the indoor fan by rotating with hand.
2. Replace indoor fan motor if not rotating smoothly.
3. Check fan motor voltage.
4. Replace indoor PCB if not at the rated voltage.
5. Check fan capacitor’s conductivity (AC Motor).
6. Replace fan capacitor if there’s conductivity.
C4
Indoor heat exchanger
thermistor short/open
1. Check the connector connection.
2. Check the sensor resistance value.
C9
Indoor room thermistor
short/open
E1
Outdoor PCB error
1. Restart the system.
2. Replace outdoor PCB.
3. Check to see that the unit is grounded.
4. Check power supply waveform.
E5
Compressor motor lock/
overload
1. Check connection on discharge pipe sensor.
2. Check discharge pipe sensor resistance value.
3. Check the EXV.
4. Check the refrigerant line on blockage or shortage.