Chimney-style range hood with a glass canopy over a cooktop

Generic photo: Bilguun Gantumur · Pexels License

Range hood fan runs only on high, runs slow, or a speed is missing

On simple switch hoods, a missing speed is usually the switch or a failed winding tap; on board-controlled hoods it can be a relay on the control. A fan that is slow on every speed points to grease-dragged bearings, a weak run capacitor on PSC motors, or airflow restriction. Check mechanical drag and airflow before electrical parts.

Single source ~45 min moderateBrands: All

Before you start

Breaker off before removing filters near the fan or opening the control cover
Live voltage checks at the switch or motor leads are caution work: insulated probes, no contact with the metal body
Discharge a run capacitor before testing it

Diagnostic steps

Unlock all 8 steps with expected values

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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