FieldBench
Mitsubishi codes

Mitsubishi

F3

Protect

Discharge thermistor

Outdoor discharge.

Walk F3 in Diagnose

3 plates — walk the one on the cabinet

First check

1 Which sensor is this code?

On Mitsubishi MSZ-FS F3 is a specific thermistor — indoor return/pipe, outdoor coil, discharge, or ambient. Unplug that sensor and ohm it vs the OEM temperature/resistance chart. Ohms. If the reading is real, high SH / low charge / overcharge per mode.

Expect: Ohms move with temperature. Not open, not shorted.

The rest of the walkthrough is Diagnose.

On the plates

  • Ohms. If the reading is real, high SH / low charge / overcharge per mode.
  • Ohms on the outdoor. Real high discharge → charge / airflow / overcharge per mode.
  • Ohms the discharge thermistor.
  • If the reading is real: overcharge, low airflow across the running indoors, or restriction.

Plates that use F3