E51 - Inverter PCB fault or power transistor overheat

What does E51 mean?

This error indicates a fault with the inverter PCB (Printed Circuit Board) in the outdoor unit, or that a power transistor within the inverter has overheated.

• Malfunctioning inverter PCB.
• Overheating power transistor due to poor airflow or excessive load.
• Electrical component failure on the inverter board.
• Damage to the PCB itself.

Click steps to track your progress.

1. 1

   Turn off the main power to the outdoor unit at the circuit breaker and allow the unit to cool down for at least 30 minutes.

2. 2

   Ensure there is proper ventilation around the outdoor unit and clear any obstructions.

3. 3

   This error points to internal electronic issues, so contact a qualified HVAC technician for diagnosis and repair of the inverter PCB or power transistor.

4. 4

   Do not attempt to repair the PCB yourself.