Fan Troubleshooting

Diagnosing fan faults from the symptom backwards: no airflow, tripping, overheating, wrong rotation, control not responding and intermittent stops.

Multimeter used to measure a fan capacitor on the capacitance range
By longwell / August 21, 2026 / Fan Engineering Guides

How to Test a Fan Capacitor with a Multimeter

Testing a capacitor takes a minute once the safety steps are done prop...

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Technician testing an ECM module separately from the motor
By longwell / August 21, 2026 / Fan Engineering Guides

Bad ECM Module vs Bad Motor: How to Tell

ECM faults split three ways: the module, the motor or the system aroun...

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Furnace blower running continuously with control board access panel open
By longwell / August 21, 2026 / Fan Engineering Guides

Furnace Blower Won’t Turn Off — Fix

A blower that runs continuously is usually being told to, either by a ...

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Cleaning a mini-split blower wheel cross-flow drum inside the indoor unit
By longwell / August 21, 2026 / Fan Engineering Guides

Cleaning a Mini-Split Blower Wheel

The cross-flow drum inside a mini-split collects a film of dust and bi...

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RV roof fan motor being replaced inside a camper roof vent
By longwell / August 21, 2026 / Fan Engineering Guides

RV Roof Fan Motor Replacement

A roof vent fan that stops usually has a short list of causes, and the...

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