Indoor unit displays P4; unit may stop; often associated with indoor coil temperature limits.

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

Blocked indoor airflow, Dirty filters, Faulty indoor coil sensor, Low refrigerant causing coil freeze, Fan speed too low

Safety: Turn off power before opening the indoor unit.

Steps:

1. Clean filters: Remove and clean indoor air filters thoroughly.
2. Check supply and return vents: Ensure furniture or curtains are not blocking airflow.
3. Inspect coil sensor: Verify the indoor coil sensor is properly attached and wiring is intact (see E2).
4. Look for ice: If the coil is frozen, turn off the unit and let it thaw completely before restarting.
5. Professional service: Persistent P4 may indicate refrigerant or fan control issues requiring a technician.

Medium 3/5

Indoor Coil Temperature Sensor (NTC)

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