Visible rust flakes or corrosion inside the furnace cabinet and on burners.

Safety first: Turn off power and gas before cleaning internal components.

• Address moisture: Check and repair any condensate leaks from the trap, hoses, or drain line.
• Vent inspection: Ensure the PVC venting is properly sealed and sloped, and that terminations are not allowing flue gases to recirculate into the intake.
• Clean rust: Light surface rust on burners and the cabinet can be brushed off with a wire brush. Severely corroded burners or heat exchanger surfaces require replacement.
• Combustion air: Make sure combustion air openings or intake piping are not blocked.
• Professional evaluation: Significant corrosion on the heat exchanger or burner supports should be evaluated by a technician for safety.