HVACopediaMitsubishi · Mini-split · Freeze protection
Freezing and overheating protection (P6)
What happens, in order
- Cooling if the pipe temperature stays under -15 C for 3 minutes after the compressor starts, the unit shuts down in a 6 minute restart-prevention mode
- If the pipe drops under -15 C for 3 minutes again within 16 minutes of that restart, the fault P6 is declared
- Heating if the pipe temperature goes over 70 C after the compressor starts, the unit goes into the 6 minute restart-prevention mode
- If over 70 C is seen again within 10 minutes of that restart, P6 is declared
- Typical causes to check dirty filter, blocked air path, wrong load, indoor fan motor or board, outdoor fan control, overcharge, refrigerant circuit clog
Timings and thresholds
| Item | Value |
|---|---|
| Freeze trigger | pipe under -15 C for 3 min |
| Freeze repeat window | 16 min |
| Overheat trigger | pipe over 70 C |
| Overheat repeat window | 10 min |
| Restart-prevention | 6 min |
Codes you may see during this
P6 P8
Applies to: Mitsubishi PEAD-RP35JA(L) indoor unit
Models
More Mitsubishi mini-split sequences
- Auto restart after power failure · Startup
- Test run with wireless remote · Startup
- Drain overflow protection (P5) · Pump/purge
Take it to the job
Sequences of operation, error codes and tips work offline in the HVACopedia app.
Source: Mitsubishi PEAD-RP35JA(L) service manual, Self-diagnosis action table P6. Written in our own words; timings can differ by model and software version, so check the manual for your exact unit.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.