OEM Service Manual: McQuay ALS Air-Cooled Screw Chiller Service Manual. Available through Daikin Applied 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 | Discharge temperature high | Warning | High compression ratio | View Details → |
| E05 | Evaporator water flow fault | Warning | Pump stopped | View Details → |
| E06 | Condenser fan fault | Warning | Fan motor failure | View Details → |
| E07 | Evaporator water temperature low | Warning | Setpoint too low | 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 | Oil leak | View Details → |
| E14 | Expansion valve fault | Warning | Valve motor failure | View Details → |
| E15 | Power supply fault | Warning | Voltage outside spec | View Details → |
| E16 | Compressor vibration alarm | Warning | Mounting bolts loose | View Details → |
| E17 | Condenser fan 2 fault | Warning | Fan 2 motor failure | View Details → |
| E18 | Compressor vibration alarm | Warning | Mounting bolts loose | View Details → |
| E19 | Pumpdown failure | Warning | Solenoid not closing | View Details → |
| E20 | Compressor surge alarm | Warning | Operating near surge line | View Details → |
| E21 | High bearing temperature | Warning | Lubrication inadequate | View Details → |
| E22 | Low subcooling alarm | Warning | Charge low | View Details → |
| E23 | High superheat alarm | Warning | Expansion valve starving | View Details → |
| E24 | Compressor start inhibit | Warning | Safety interlock preventing start | View Details → |
| E25 | Evaporator approach temperature high | Warning | Fouled tubes | View Details → |
| E26 | Condenser approach temperature high | Warning | Fouled condenser | View Details → |
| E27 | Chiller staging error | Warning | Staging logic error | View Details → |
| E28 | Energy efficiency alarm | Warning | Below expected efficiency | View Details → |
| E29 | Compressor runtime exceeded | Warning | Exceeded max runtime | View Details → |
| E30 | Refrigerant level alarm | Warning | Level sensor low | View Details → |
Disclaimer: All McQuay ALS 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.