Whole-house humidifier not adding moisture

Bypass and fan-powered humidifiers need water, airflow and a call from the humidistat. Check the season damper, water valve, scaled water panel and humidistat before testing the 24 V solenoid valve.

Cross-checked ~45 min moderateBrands: Aprilaire, Honeywell, Carrier / Bryant, All

Before you start

Turn off the furnace and humidifier power and close the water valve before servicing.

Diagnostic steps

Unlock all 4 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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