Indoor unit displays F3, often related to intake or discharge air temperature

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Open or shorted intake/discharge thermistor, Sensor out of position, Damaged harness, Faulty indoor PCB

Safety first: Turn off power before removing covers.

Steps:

Locate sensor: Find the intake or discharge air thermistor near the air outlet or behind the front grille.
Check mounting: Ensure the sensor is correctly positioned in the airflow and not dangling.
Inspect wiring: Check for pinched or cut wires and repair as needed.
Measure resistance: Test the thermistor resistance and compare to the service manual chart. Replace if out of range.
Replace PCB: If the sensor is good and F3 persists, the indoor PCB may need replacement.

Medium 3/5

Indoor Intake/Discharge Air Thermistor

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