Indoor unit displays F4, system may not heat or cool correctly

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 condenser coil sensor (T5), Sensor not properly attached to coil, Damaged sensor wiring, Faulty outdoor PCB sensor input

Safety first: Disconnect power to the outdoor unit before servicing.

Locate sensor: Find the T5 sensor clipped to the outdoor condenser coil tubing.
Check attachment: Ensure the sensor is firmly clipped to the pipe and has good thermal contact.
Inspect wiring: Look for cuts, abrasions, or rodent damage to the sensor cable. Reseat the connector on the PCB.
Replace sensor: If F4 persists, replace the condenser temperature sensor. If the error still does not clear, the outdoor PCB may be defective.

Medium 3/5

Outdoor Condenser Temperature Sensor (T5)

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