OEM Service Manual: Lennox SCA Air-Cooled Scroll Chiller Service Manual. Available through Lennox Commercial technical support.
30 codes
| Fault Code | Alarm Description | Severity | Probable Causes | Action |
|---|---|---|---|---|
| E01 | Supply air temperature sensor fault | Warning | Sensor element failure | View Details → |
| E02 | Return air temperature sensor fault | Warning | Sensor element drifted out of calibration | View Details → |
| E03 | Outdoor air temperature sensor fault | Warning | Sensor moisture ingress | View Details → |
| E04 | Coil temperature sensor fault | Warning | Sensor element failure | View Details → |
| E05 | High pressure switch activated | Critical | Condenser coil fouled restricting airflow | View Details → |
| E06 | Low pressure switch activated | Warning | Low refrigerant charge from leak | View Details → |
| E07 | Compressor overload | Warning | Compressor motor bearing wear | View Details → |
| E08 | Freeze protection | Critical | Evaporator water temperature approaching freezing | View Details → |
| E09 | Overcurrent protection | Critical | Compressor motor overload | View Details → |
| E10 | Phase monitor fault | Warning | Phase loss on one conductor | View Details → |
| E11 | Compressor motor protection | Warning | Internal motor protector tripped from high temperature | View Details → |
| E12 | Discharge temperature high | Warning | Compression ratio too high from high head pressure | View Details → |
| E13 | Oil pressure fault | Warning | Oil pump failure or wear | View Details → |
| E14 | Communication fault | Warning | Network cable damaged or disconnected | View Details → |
| E15 | Expansion valve fault | Warning | Electronic expansion valve motor failure | View Details → |
| E16 | Fan motor fault | Warning | Fan motor winding failure | View Details → |
| E17 | Low pressure safety 2 | Warning | Low refrigerant charge on circuit 2 | View Details → |
| E18 | High pressure safety 2 | Critical | Condenser 2 fouled | View Details → |
| E19 | Compressor 2 overload | Warning | Compressor 2 motor bearing failure | View Details → |
| E20 | Compressor 2 motor protection | Warning | Internal motor protector tripped in compressor 2 | View Details → |
| E21 | Discharge temperature high 2 | Warning | Compression ratio too high on circuit 2 | View Details → |
| E22 | Oil pressure fault 2 | Warning | Oil pump 2 failure | View Details → |
| E23 | Remote control fault | Warning | Remote control communication cable damaged | View Details → |
| E24 | Alarm relay fault | Warning | Alarm relay coil failure | View Details → |
| E25 | Compressor capacity staging fault | Warning | Compressor staging logic error | View Details → |
| E26 | Cooling tower interlock fault | Warning | Cooling tower not running signal | View Details → |
| E27 | Water flow proving 2 | Warning | Water flow proving switch on circuit 2 not closing | View Details → |
| E28 | Surge protection activated | Warning | Voltage surge detected by surge protection device | View Details → |
| E29 | Condensate level high | Warning | Condensate drain blocked | View Details → |
| E30 | Economizer fault | Warning | Economizer damper actuator failure | View Details → |
Disclaimer: All Lennox SCA 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.