U8

Outdoor fan motor error

Mitsubishi Electric · PUZ-HA30/36NHA4 Outdoor Unit

What does U8 mean?

The outdoor fan motor is abnormal if its rotational frequency is detected as abnormal during operation, specifically 100 rpm or below for 1 second at 30°C or more, or 30 rpm or below/1000 rpm or more for 1 minute continuously. This indicates a problem with the fan motor or its control circuit. Failing to resolve this can lead to insufficient heat exchange, compressor overheating, and overall system performance degradation.

Repair Steps

  1. 1

    Check the DC fan motor for physical obstructions, bearing issues, or signs of failure. Check or replace it as necessary.

  2. 2

    Measure the voltage supplied to the outdoor circuit controller board during fan operation.

  3. 3

    Replace the outdoor circuit controller board if the fan motor is confirmed functional and the error persists.

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Verified technical data. Last updated: March 2026
Source: Mitsubishi Electric PUZ-HA30/36NHA4 Outdoor Unit