Heater operates but causes noticeable vibration and rattling noises in the cabinet.

Safety first: Turn off power and allow moving parts to stop before touching the blower or internal components.

Step-by-step checks:

• Tighten mounting hardware: Check all accessible screws and bolts securing the blower, burner tray, and panels. Tighten as needed.
• Inspect blower wheel: Remove the blower housing cover (if serviceable) and check for leaves, insects, or debris stuck in the wheel. Clean carefully.
• Secure flue: Ensure the flue pipe is properly supported and not resonating against walls or the heater casing.
• Check cabinet panels: Add or replace missing screws on access panels and doors to reduce rattling.

When to stop: If vibration persists or seems to come from inside the blower motor, the motor or wheel may need replacement by a technician.