Outdoor Board LED1 (green) blinks four times and LED2 (red) blinks five times alternately - Open/short of outdoor thermistors (TH3, TH32, TH33, TH6, TH7 and TH8)

What does U9 mean?

During startup or operation, the outdoor unit's LED1 (green) blinks four times and LED2 (red) blinks five times alternately, indicating an open circuit or short circuit in various outdoor thermistors (TH3, TH32, TH33, TH6, TH7, TH8).

• Open circuit in outdoor thermistors.
• Short circuit in outdoor thermistors.
• Disconnected connectors for relevant outdoor thermistors.

Click steps to track your progress.

1. 1

   Check if connectors (TH3, TH32, TH33, TH4, and TH7/6) on the outdoor controller board and connector (CN3) on the outdoor power board are not disconnected.

2. 2

   Measure the resistance values of the outdoor thermistors using a tester to check for open or short circuits.

3. 3

   Ensure all wiring connections to the outdoor thermistors are secure and undamaged.