Furnace rattles or vibrates loudly when running.

Safety: Turn off power before tightening hardware.

• Tighten panels: Ensure all furnace access panels are properly seated and screws are tight.
• Secure blower housing: Check mounting bolts and brackets for looseness and tighten as needed.
• Inspect blower wheel: Look for bent fins or heavy dust buildup. Clean and straighten minor bends.
• Check duct supports: Secure any loose metal ducts connected to the furnace.