Aprilaire dehumidifier trips circuit breaker or blows fuse when starting

Safety first: Turn off the breaker and do not repeatedly reset it. Risk of fire or shock exists.

• Inspect power cord: Check the cord for cuts, burns, or crushed sections. Replace the Aprilaire power cord if damaged.
• Check for obvious shorts: Remove the access panel and look for burned wires, loose connections, or wires contacting sharp metal edges.
• Isolate components: With power disconnected, disconnect the compressor and fan motor leads from the board. Then restore power and see if the breaker holds. Reconnect components one at a time to identify which causes the trip.
• Test motors: Measure resistance to ground from compressor and fan motor leads. Any continuity to ground indicates a shorted winding and the component must be replaced.
• Use correct breaker: Verify the circuit breaker size matches the unit’s nameplate amperage. Do not oversize the breaker.
• Replace failed component: Replace the shorted Aprilaire compressor or fan motor as required. If internal wiring is damaged, repair with proper gauge wire and connectors.