OEM Service Manual: McQuay PFS Air-Cooled Scroll Chiller Service Manual. Available through Daikin Applied (formerly McQuay) technical support.
30 codes
| Fault Code | Alarm Description | Severity | Probable Causes | Action |
|---|---|---|---|---|
| E01 | Compressor high pressure protection | Critical | Condenser coil fouled | View Details → |
| E02 | Compressor low pressure protection | Warning | Low refrigerant charge | View Details → |
| E03 | Compressor motor overload | Critical | Motor bearing failure | View Details → |
| E04 | Compressor discharge temperature high | Warning | High compression ratio | View Details → |
| E05 | Evaporator water flow fault | Warning | Pump stopped | View Details → |
| E06 | Condenser water flow fault | Warning | Condenser pump stopped | View Details → |
| E07 | Freeze protection activated | Critical | Evaporator water temperature near freezing | View Details → |
| E08 | Sensor fault | Warning | Sensor element failure | View Details → |
| E09 | Communication fault | Warning | Network cable fault | View Details → |
| E10 | Phase loss or reversal | Critical | Missing phase | View Details → |
| E11 | Overcurrent protection | Critical | Motor overload | View Details → |
| E12 | Oil pressure low | Critical | Oil pump wear | View Details → |
| E13 | Oil level low | Critical | Refrigerant leak carrying oil | View Details → |
| E14 | Expansion valve fault | Warning | Valve motor failure | View Details → |
| E15 | Power supply fault | Warning | Voltage outside spec | View Details → |
| E16 | Condenser fan fault | Warning | Fan motor failure | View Details → |
| E17 | Compressor 2 fault | Warning | Compressor 2 motor overload | View Details → |
| E18 | Compressor 3 fault | Warning | Compressor 3 motor overload | View Details → |
| E19 | Compressor 4 fault | Warning | Compressor 4 overload | View Details → |
| E20 | Head pressure control fault | Warning | Head pressure control valve stuck | View Details → |
| E21 | Ambient temperature low limit | Warning | Ambient temperature below minimum operating limit | View Details → |
| E22 | Chilled water temperature sensor drift | Warning | Sensor calibration drift | View Details → |
| E23 | Condenser water temperature sensor drift | Warning | Sensor calibration drift | View Details → |
| E24 | Compressor sequence fault | Warning | Compressor staging sequence error | View Details → |
| E25 | Pump interlock fault | Warning | Water pump auxiliary contact lost | View Details → |
| E26 | Flow proving fault | Warning | Flow proving switch not closing | View Details → |
| E27 | Remote start/stop fault | Warning | Remote start/stop signal not received | View Details → |
| E28 | Alarm summary overflow | Warning | Too many active alarms for display | View Details → |
| E29 | Clock/calendar fault | Warning | RTC battery depleted | View Details → |
| E31 | High ambient temperature alarm | Warning | Ambient exceeds design limit | View Details → |
Disclaimer: All McQuay PFS fault code data is for reference only. Do not use this information to replace certified professional HVAC technician judgment. Always refer to original OEM official service manual.