Power Transistor Overheat

What does E51 mean?

The power transistor has overheated, indicating excessive heat generation, potentially due to a fault or overload condition. This protects the inverter from damage.

• Overheating of the inverter's power transistors due to insufficient cooling.
• Excessive current draw through the power transistors.
• Faulty heatsink thermal paste or inadequate fan operation for the inverter.
• Short-term overload condition during motor startup.

Click steps to track your progress.

1. 1

   Inspect the inverter unit's heatsink for dust accumulation and ensure proper ventilation clearances.

2. 2

   Verify the outdoor fan operation is providing adequate cooling to the inverter components, checking fan speed and direction.

3. 3

   Measure the current draw of the compressor and compare to specification, checking for overload conditions.

4. 4

   Check for loose electrical connections within the inverter module's power circuit.