Model - McQuay M5CKY28ER Technical Manual

Troubleshooting
Error Code
Error Codes
0 Normal
U0 Insuffi cient gas
U2 DC voltage out of range
U4 Communication error
Signal transmission error
U7
(on outdoor unit PCB)
UA Installation error
Communication Error (indoor and
UF
outdoor) piping and wiring
UH Anti-freeze function in other room
A1 Indoor PCB error
A3 Water pump error
A5 Antifreeze
48
Error Description Action
No action.
1. Check sensor connection.
2. Check stop valve.
3. Check for gas leak.
4. Check the EXV.
5. Check H8.
1. Check the supply voltage.
2. Check the outdoor fan by rotating with hand.
3. Restart the system.
4. Check power supply waveform.
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.
1. Restart the system.
2. Replace outdoor PCB.
3. Long term monitor on external factor.
1. Check the indoor and outdoor unit model name.
2. Check the part code on the indoor and outdoor
PCB.
1. Check the wiring and piping between indoor and
outdoor units.
2. Check refrigerant level.
3. Check refrigerant line on blockage.
1. Check which indoor having error A5.
2. Check the supply voltage.
3. Check the indoor and outdoor model name.
1. Check connector connection.
2. Replace indoor PCB.
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.
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.
M5LCY-II_(i)