Safety first: Turn off power before tightening or removing any panels.

Check cabinet panels: Tighten all screws securing the front, side, and top panels. Replace missing screws.
Inspect blower assembly: Remove the blower access panel and check that the blower is firmly mounted. Tighten mounting hardware as needed.
Remove debris: Clear any leaves or objects from the blower wheel and surrounding area.
Balance issues: If the blower wheel is bent or damaged, replace the blower assembly to prevent bearing damage.

Heater cabinet vibrates excessively or rattles loudly when running.

Possible Causes