Large rental dehumidifier unit on a job site

Generic photo: DesiccantDryAir · CC BY-SA 4.0

Dehumidifier fan not running

Confirm it is a real fault: many units run the fan on after the compressor stops, and some stop the fan at setpoint. Then check for a jammed blade, a loose motor plug, the fan capacitor (on PSC motors) and the board output.

Single source ~45 min moderateBrands: All

Before you start

Unplug before opening; live voltage checks at the board are caution steps
Discharge any capacitor before handling it

Diagnostic steps

Unlock all 5 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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