MRCOOL error codes
MRCOOL DIY ductless mini-splits show error codes on the indoor unit's display. Gen 4 and Gen 5 units use longer codes such as EL 01 and EH 0A for faults that older units show as E1 or E0, so check your unit's generation when you look up a code. On a new DIY install, most codes trace back to the line-set connections, the service valves or the communication wire.
MRCOOL air conditioner codes
| Code | What it means | Fix |
|---|---|---|
| E1also EL 01 | Indoor and outdoor units not communicating | Moderate DIY |
| ECalso EL 0C | Refrigerant leak or low refrigerant detected | Moderate DIY |
| EH 0Aalso EH 00, E0 | Indoor unit EEPROM (control board memory) error | Technician job |
| E5also EH 61 | Indoor coil temperature sensor fault | Moderate DIY |
| P1also PC 01 | Over or under voltage protection | Technician job |
| P4also PC 04 | Inverter compressor drive error | Technician job |
| P6also PC 03 | Low pressure protection | Moderate DIY |
| F1also EC 53 | Outdoor ambient temperature sensor fault | Technician job |
| F5also EC 07 | Outdoor fan speed out of control | Moderate DIY |
| E3also EH 03 | Indoor fan speed out of control | Moderate DIY |
| P0also PC 00 | Inverter module (IPM) protection | Technician job |