Furnace vibrates excessively and causes rattling noises in ducts and nearby structures.

Safety: Turn off power before inspection.

Steps:

• Inspect fan wheel: Check for missing pieces, bent blades, or heavy dust on one side of the wheel. Clean evenly around the circumference.
• Tighten fasteners: Tighten all screws securing the fan housing, motor mounts, and cabinet panels.
• Check ductwork: Ensure ducts are properly supported and not resting directly on structural members that can amplify vibration.

Professional service: If vibration persists, the fan wheel may need replacement or rebalancing by a technician.