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Mitsubishi Error Code P6: Coil freeze or overheat protection (Heat Pump)

Updated · by Aurora Star Tech Inc.

Mitsubishi error code P6 on a heat pump means: Coil freeze or overheat protection. It is also called Mitsubishi diagnostic code P6.

High severityHeat PumpMr. Slim PEAD-RP JA(L) ducted indoor unit

Homeowner? What Mitsubishi code P6 means for you

Call a technician Your heat pump is reporting: Coil freeze or overheat protection. The heat pump has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Safe things you can check yourself

  • Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
  • Check both breakers and the outdoor disconnect box beside the outdoor unit; all should be ON.
  • Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
  • In winter, keep snow and ice off and away from the outdoor unit. A short defrost cycle with steam is normal.
  • Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Mitsubishi error code P6 mean?

Cooling: the indoor coil stayed below -15°C for 3 minutes after the compressor started, twice within 16 minutes. Heating: the coil went above 70°C, twice within 10 minutes. The unit pauses 6 minutes after the first event and locks out with P6 on the second.

Applies to: PEAD-RP35/50/60/71/100/125/140JA and JA(L) ducted indoor units (220-240 V models)

Common causes of Mitsubishi code P6

  • Dirty filter or low airflow
  • Supply air short-cycling back to the return
  • Running outside the allowed temperature range (very cold in cooling, very hot in heating)

A technician checks these and 5 other possible causes on site before replacing any part.

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Mitsubishi models that use code P6

PEAD-RP35JAPEAD-RP35JALPEAD-RP50JAPEAD-RP50JALPEAD-RP60JAPEAD-RP60JALPEAD-RP71JAPEAD-RP71JALPEAD-RP100JAPEAD-RP100JALPEAD-RP125JAPEAD-RP125JALPEAD-RP140JAPEAD-RP140JAL

Other Mitsubishi Heat Pump codes

CodeMeaning
E7Indoor unit transmit error to outdoor unit
FbIndoor control board memory error
P1Room (intake) air sensor TH1 open or shorted
P2Liquid pipe sensor TH2 open or shorted
P4Drain float switch disconnected
P5Drain overflow - float switch wet with pump running
P8Pipe temperature out of range (coil not cooling or heating)
P9Coil sensor TH5 open or shorted
PAWater leak detected

All Mitsubishi Heat Pump error codes →

Mitsubishi code P6: homeowner questions

What does Mitsubishi code P6 mean?

Coil freeze or overheat protection. Cooling: the indoor coil stayed below -15°C for 3 minutes after the compressor started, twice within 16 minutes. Heating: the coil went above 70°C, twice within 10 minutes. The unit pauses 6 minutes after the first event and locks out…

Is it safe to keep using my heat pump with code P6?

It depends on the cause. The heat pump has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Can I reset Mitsubishi code P6 myself?

You can try one reset (power off for 30 seconds, then on). If Mitsubishi code P6 comes back, the cause is still there and a licensed technician should check it.

Who can fix Mitsubishi code P6 near me?

Aurora Star Tech Inc. repairs Mitsubishi heat pumps in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: AC Running But Not Cooling: What to Check · Heat Pump Not Heating or Blowing Cold Air

Troubleshooting guides

Source: Mitsubishi Electric PEAD-RP35-140JA(L) Service Manual, 10-3 Self-diagnosis action table, p.32. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency HVAC Service

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