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Mitsubishi Error Code Fb: Indoor control board memory error (Heat Pump)

Updated · by Aurora Star Tech Inc.

Mitsubishi error code Fb on a heat pump means: Indoor control board memory error. It is also called Mitsubishi diagnostic code Fb.

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

Homeowner? What Mitsubishi code Fb means for you

Call a technician Your heat pump is reporting: Indoor control board memory error. 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 Fb mean?

The indoor board cannot read its non-volatile memory.

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 Fb

  • Faulty indoor control board
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 Fb

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

Other Mitsubishi Heat Pump codes

CodeMeaning
E2Remote controller clock error
E3Remote controller cannot transmit
E4Indoor unit not receiving from remote controller
E5Indoor unit cannot transmit to remote controller
E6Indoor/outdoor communication - indoor not receiving
E7Indoor unit transmit error to outdoor unit
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
P6Coil freeze or overheat protection
P8Pipe temperature out of range (coil not cooling or heating)

All Mitsubishi Heat Pump error codes →

Mitsubishi code Fb: homeowner questions

What does Mitsubishi code Fb mean?

Indoor control board memory error. The indoor board cannot read its non-volatile memory.

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

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 Fb myself?

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

Who can fix Mitsubishi code Fb 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.34. 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

647-657-2977