McQuay M5CKY28ER User Manual

Troubleshooting M5LCY-II_(i)
48
Error Code
Error Codes Error Description Action
0 Normal No action.
U0 Insuffi 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.
U7
Signal transmission error
(on outdoor unit PCB)
1. Restart the system.
2. Replace outdoor PCB.
3. Long term monitor on external factor.
UA Installation error
1. Check the indoor and outdoor unit model name.
2. Check the part code on the indoor and outdoor
PCB.
UF
Communication Error (indoor and
outdoor) piping and wiring
1. Check the wiring and piping between indoor and
outdoor units.
2. Check refrigerant level.
3. Check refrigerant line on blockage.
UH Anti-freeze function in other room
1. Check which indoor having error A5.
2. Check the supply voltage.
3. Check the indoor and outdoor model name.
A1 Indoor PCB error
1. Check connector connection.
2. Replace indoor PCB.
A3 Water pump error
1. Check for short circuit.
2. Check connection on drain pump.
3. Restart the system.
4. Check the drain water level.
5. Check fl oat switch connection.
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.

McQuay M5CKY28ER Specifications

General

Brand	McQuay
Model	M5CKY28ER
Category	Air Conditioner
Language	English