What does 399 mean?

The temperature sensor monitoring the heat sink of Fan 2 in the outdoor unit is reporting an error.

• Heat sink temperature sensor failure
• Loose or damaged sensor wiring
• Overheating issue affecting the sensor

Click steps to track your progress.

1. 1

   Inspect the wiring of the heat sink temperature sensor for Fan 2.

2. 2

   Ensure the sensor is properly positioned and making contact.

3. 3

   Check if the heat sink is clean and free of dust or debris.

4. 4

   This error may indicate a need for component replacement.