Lennox Error Codes
Every Lennox error code we have catalogued, with what it means on site — 26 codes in total. In R-Pro, tap any code to get the meaning, likely causes and inspection steps, even with no signal in the plant room.
26 codes
| Code | What it means |
|---|---|
| E1 | High pressure protection |
| E2 | Indoor coil freeze protection |
| E3 | Outdoor coil blockage |
| E4 | Discharge line temperature protection |
| E5 | Over-current protection |
| E6 | Indoor/outdoor communication failure |
| E8 | System overload malfunction |
| EE | EEPROM memory failure |
| F0 | Lack of refrigerant / coil gathering |
| F1 | Indoor ambient temp sensor short |
| F2 | Indoor evaporator temp sensor short |
| F3 | Outdoor ambient sensor (RT4) fault |
| F4 | Outdoor coil sensor fault |
| F5 | Discharge line sensor error |
| F6 | Compressor overload limit |
| H1 | Defrosting mode |
| H3 | Compressor overload protection / sensor fault |
| H4 | Compressor high-temperature protection |
| H5 | IPM protection |
| H6 | IDU fan motor blocked / no communication |
| HC | PFC protection |
| L3 | Outdoor DC fan motor malfunction |
| LP | Indoor/outdoor unit mismatch |
| PH | High voltage protection |
| PL | Low voltage protection |
| U8 | Zero-crossing inspection circuit error |
Official Lennox source / manual ↗
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