McQuay Air Conditioner Error Codes McQuay is one of the largest air conditioning, heating, ventilating and refrigeration companies in the world. They have earned a worldwide reputation for providing a full line of quality products and expertise to meet the demands of their customers.
McQuay Air Conditioner Error Code Solutions
| Error Codes | Problem |
|---|---|
| E1 | Compressor 2 low pressure faulty |
| E2 | Compressor 2 high pressure faulty |
| E3 | Compressor 2 overload |
| E4 | Indoor coil 2 temperature sensor fault |
| E5 | System 2 leaving water temperature 2 faulty |
| F2 | Indoor coil 1 temperature sensor fault |
| F4 | Return air temperature sensor fault |
| F6 | Communication faulty |
| F9 | Compressor 1 refrigerant leak |
| FE | Compressor 2 refrigerant leak |
| H1 | Compressor 1 overload |
| H4 | Compressor 1 high pressure faulty |
| L1 | Compressor 1 low pressure faulty |
| L3 | Temperature of water entering too high or low |
| L4 | Water flow switch faulty |
| L5 | System 1 leaving water temperature 1 faulty |
Single Split Inverter-Y Model Indoor Series
| Error Codes | Error Description |
|---|---|
| 0 | Normal |
| F6 | Heat exchanger overheat |
| U0 | Insufficient gas |
| H0 | Compressor sensor system abnormality |
| U2 | DC voltage out of range |
| H3 | High pressure switch error |
| U4 | Communication error |
| H6 | Position sensor abnormality |
| U7 | Signal transmission error (on outdoor unit PCB) |
| H8 | AC current sensor error |
| UA | Installation error |
| H9 | Outdoor air thermistor short / open |
| UF | Communication Error (indoor and outdoor) piping and wiring |
| J1 | Pressure sensor error |
| UH | Anti-freeze function in other room |
| J3 | Compressor discharge pipe thermistor short /open / misplaced |
| A1 | Indoor PCB error |
| J5 | Suction pipe thermistor short/ open |
| A3 | Water pump error |
| J6 | Outdoor heat exchanger |
| A5 | Antifreeze |
| J7 | Subcooling heat exchanger thermistor short/ open |
| A6 | Indoor fan motor abnormal |
| J8 | Liquid pipe thermistor short/ open |
| C4 | Indoor heat exchanger thermistor short/ open |
| J9 | Gas pipe thermistor abnormality |
| C9 | Indoor room thermistor short/ open |
| LC | Communication error (control PCB and inverter PCB) |
| L1 | Outdoor PCB error |
| L3 | Electrical box temperature rise |
| L4 | Heat sink overheat |
| E1 | Outdoor PCB error |
| E3 | High pressure protection |
| E4 | Low pressure protection |
| E5 | Compressor motor lock |
| L5 | IPM error / IGBT error |
| E6 | Compressor start-up error |
| L8 | Electrical thermal switch |
| E7 | Outdoor DC fan motor lock |
| L9 | Stall prevention |
| E8 | Ac input over current |
| P1 | Open phase or voltage unbalance |
| E9 | EXV error |
| P4 | Heat sink thermistor short / open |
| EA | 4-way valve error |
| PJ | Capacity setting error |
| F3 | Discharge pipe overheat |
Wall Mounted K-Series Inverter-Y model
| Error Codes | Meaning |
|---|---|
| 00 | Normal |
| UA | Indoor-outdoor Unit Combination Fault |
| UO | Refrigerant Shortage |
| U2 | Drop Voltage Or Main Circuit Overvoltage |
| U4 | Failure Of Transmission (Between Indoor Unit And Outdoor Unit) |
| A1 | Indoor Pcb Defectiveness |
| A5 | High Pressure Control Or Freeze-up Protector |
| A6 | Fan Motor Fault |
| C4 | Faulty Heat Exchanger Temperature Sensor |
| C9 | Faulty Suction Air Temperature Sensor |
| EA | Cooling-heating Switching Error |
| E1 | Circuit Board Fault |
| E5 | Ol Started |
| E6 | Faulty Compressor Start Up |
| E7 | Dc Fan Motor Fault |
| E8 | Overcurrent Input |
| F3 | High Temperature Discharge Ppe Control |
| F6 | High Pressrue Control (In Cooling) |
| H0 | Sensor Fault |
| H6 | Operation Fault Due To Faulty Position Detection Sensor |
| H8 | Dc Current Sensor Fault |
| H9 | Faulty Suction Air Temperature Sensor |
| J3 | Faulty Discharge Pipe Temperature Sensor |
| J6 | Faulty Heat Exchanger Temperature Sensor |
| L3 | Electrical Parts Heat Fault |
| L4 | High Temperature At Inverter Circuit Heatsink |
| L5 | Output Overcurrent |
| P4 | Faulty Inverter Circuit Heatsink Temperature Sensor |
Error Diagnosis by Wired Controller (MC301):
E0: System malfunction
E1: Sensor Broken (TH1 discharge Temp.)
E2: Sensor Broken (TH2 inlet coil 1#)
E3: Sensor Broken (TH3 mid coil 1#)
E4: Sensor Broken (TH4 inlet coil 2#)
E5: Sensor Broken (TH5 mid coil 2#)
E6: Sensor Broken (TH6 inlet coil 3#)
E7: Sensor Broken (TH7 mid coil 3#)
E8: Sensor Broken (TH8 ambient temp)
E9: Sensor Broken (TH9 outlet coil)
EA: Sensor Broken (TH10 subcool outlet)
EB: Sensor Broken (TH11 subcool suction)
EC: Sensor Broken (TH12 suction)
EF: Emergency Run
F0: Outdoor Storage Malfunction
F1: Sensor Broken (indoor inlet coil)
F2: Sensor Broken (indoor mid coil)
F3: Sensor Broken (indoor outlet coil)
F4: Sensor Broken (indoor return air)
F5: Sensor Broken (indoor supply air)
F6: Indoor and controller communication malfunction
F7: Ambient temp exceed the limit
F8: 4WV malfunction
F9: Refrigerant leakage
FA: Controller storage malfunction
FB: Water Pump (indoor water pump)
FC: Indoor and outdoor communication malfunction
FE: Outdoor master and slave communication malfunction
H0: Digital comp overload
H1: Fixed Comp1 overload
H2: Fixed Comp2 overload
H3: Fixed Comp3 overload
H4: High pressure too high
H5: Sensor broken, high pressure
H6: Discharge temp too high
L0: Super heat too low
L1: Low pressure too low
L2: Sensor broken, low pressure
10: System malfunction
11: Sensor broken (slave TH1 discharge temp)
12: Sensor broken (slave TH2 inlet coil 1#)
13: Sensor Broken (slave TH3 mid coil 1#)
14: Sensor broken (slave TH4 inlet coil 2#)
15: Sensor broken (slave TH5 mid coil 2#)
16: Sensor broken (slave TH6 inlet coil 3#)
17: Sensor broken (slave TH7 mid coil 3#)
18: Sensor broken (slave TH8 ambient temp)
19: Sensor broken (slave TH9 outlet coil)
1A: Sensor broken (slave TH10 subcool outlet)
1B: Sensor broken (slave TH11 subcool suction)
1C: Sensor Broken (slave TH12 suction)
1F: Emergency run (slave)
20: Outdoor storage (slave)
27: Ambient temp exceed the limit (slave)
28: 4WV malfunction (slave)
29: Refrigerant leakage (slave)
30: Digital comp overload (slave)
31: Fixed comp1 overload (slave)
32: Fixed comp2 overload (slave)
33: Fixed comp 3 overload (slave)
34: High pressure too high (slave)
35: Sensor broken, high pressure (slave)
36: Discharge temp too high (slave)
40: Super heat too low (slave)
41: Low pressure too low (slave)
42: Sensor broken, low pressure (slave)
Mcquay Cassette AC Error Codes
Wired Remote Control (Universal Board)
Display: E1 Blinking
Faulty Indication: Room sensor contact loose/ short
Display: E2 Blinking
Faulty Indication: Indoor coil sensor contact loose/ short
Display: E3 Blinking
Faulty Indication: Outdoor coil sensor contact loose/ short
Display: E4 Blinking
Faulty Indication: Compressor overload
Display: E5 Blinking
Faulty Indication: Gas leak
Display: E6 Blinking
Faulty Indication: Pump faulty
Display: Heat LED Blinking
Faulty Indication: Outdoor defrost (for Heatpump only)
McQuay PTAC Error Codes
Remote Controller Error Display:
E01: Room temperature sensor open. Automatically reset to restoration error.
E02: Room temperature sensor short. Automatically reset to restoration error.
E03: Error input from indoor unit or Outdoor unit.
McQuay Air Conditioner Troubleshooting
When a malfunction of the air conditioner unit is detected, immediately switch off the main power supply before proceeding with the following troubleshooting procedures.
The following are common fault conditions and simple troubleshooting tips. If any other fault conditions which are not listed occur, contact your nearest local dealer. DO NOT attempt to troubleshoot the unit by yourself.
| Fault Conditions | Possible causes / corrective actions |
|---|---|
| The air conditioner unit will not resume after power failure. | The auto restart function is not functioning. Please turn on the unit with the wireless / wired controller. |
| The airfl ow is too slow or room cannot be cooled suffi ciently. |
|
| Discharge airfl ow has bad odor. |
|
| Condensation on the front air grille of the indoor unit. |
|
| Water fl owing out from the air conditioner. | Switch off the unit and contact your nearest dealer. This might be due to tilted installation. |
| Hissing airfl ow sound from the air conditioner unit during operation. | Liquid refrigerant fl owing into the evaporator coil. |
| The wireless controller display is dim. |
|
| Compressor operates continuously. |
|
| No cool air comes out during cooling cycle, or no hot air comes out during heating cycle. |
|
| On heating cycle, warm air does not come out. | Unit is in defrost mode. Heating operation will resume after defrost cycle ends. |