Fan speed feedback fault: when the fan is spinning but the controller reports an alarm

In EC or DC fans, the controller may receive speed feedback. If the feedback is lost, a fault may appear even if the impeller appears to be rotating.

Potential causes

Feedback signal failure, wiring issues, motor electronic module, or incorrect command signal.

What to check

Power supply, command, feedback, and actual RPM.

Important

Visual inspection alone is not enough to confirm that the fan is operating correctly.