E41

Inverter Power Transistor Overheat

Mitsubishi Electric · FR-D700 Inverter

What does E41 mean?

The power transistor for the inverter has overheated, indicating excessive heat generation, potentially due to a fault or overload condition. This poses a risk to the inverter module's longevity.

Common Causes

  • Inverter power transistor (IGBT) has overheated.
  • Insufficient cooling for the inverter module.
  • Overcurrent condition causing excessive heat.
  • Faulty heatsink or fan for the inverter.
  • High ambient temperature impacting inverter operation.

Repair Steps & Checklist

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.

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Verified technical data. Last updated: March 2026

Related Faults

Source: Mitsubishi Electric FR-D700 Inverter