F21 (10 LED flashes) - Frost-removing temperature sensor failure

What does F21 mean?

The outdoor unit's LED1 flashes ten times, indicating a failure with the sensor responsible for detecting frost during defrost cycles.

• Faulty frost-removing temperature sensor
• Loose connection of the sensor wiring
• Damaged wiring to the sensor
• Outdoor unit PCB issue

Click steps to track your progress.

1. 1

   Turn off the AC unit at the main power supply and wait 15 minutes, then restart it.

2. 2

   Ensure there isn't excessive ice buildup on the outdoor unit's coils.

3. 3

   If the error persists, contact a qualified technician to inspect or replace the sensor.