P4 - Drain sensor abnormal in indoor unit

What does P4 mean?

This error indicates a problem with the drain sensor in the indoor unit, which monitors the water level in the drain pan.

• Faulty drain sensor.
• Loose or disconnected wiring to the drain sensor.
• Clogged drain pan or condensate line triggering the sensor.
• Malfunctioning drain pump (if present).

Click steps to track your progress.

1. 1

   Turn off the power to the indoor unit at the circuit breaker.

2. 2

   Check the condensate drain pan for excess water and the drain line for clogs. Clear any blockages.

3. 3

   Ensure the drain sensor is properly seated and its wiring is secure (professional inspection recommended).

4. 4

   If the sensor is faulty, contact a qualified technician for replacement.