Drain Sensor Abnormal

What does P4 mean?

The indoor unit's drain sensor is abnormal, indicating a fault with its circuit. This sensor monitors the condensate drain pan level to prevent overflow, and a fault can lead to water leakage.

1. 1

   Measure the resistance or output of the drain sensor according to manufacturer specifications.

2. 2

   Inspect the sensor's wiring and connector on the indoor unit PCB for damage, corrosion, or secure seating.

3. 3

   Check the drain pan for actual water level and visually verify float switch operation if applicable.