Fault code 91 — The unit turns off due the IPM board over heating fault

What does 91 mean?

The unit has shut down because the Intelligent Power Module (IPM) board has overheated. This can be caused by high outdoor temperatures, low fan speed, improper installation, or low supply power.

• The outdoor ambient temp. is too high
• The speed of the out fan motor is too low if the fan motor is AC fan motor
• The outdoor unit is not installed in accordance with the standard
• The supply power is too low

Click steps to track your progress.

1. 1

   Ensure the unit is operating within its specified ambient temperature range.

2. 2

   Check the outdoor fan motor and its capacitor for proper operation.

3. 3

   Verify the unit's installation meets the standards outlined in the manual.

4. 4

   Confirm the supply power is adequate.