Boiler emits rumbling or roaring noise from burner area

Critical safety warning: Combustion problems can produce carbon monoxide. If you suspect unsafe combustion, shut down the boiler and call a professional.

• Visual check: Look through the sight glass (if present). Flame should be stable and mostly blue with minimal yellow tips.
• Inspect burner: With power and gas off, remove burner assembly and clean burner ports with a soft brush and vacuum.
• Check air openings: Ensure combustion air openings and intake are not blocked.
• Professional adjustment: Gas pressure and combustion must be checked and adjusted by a licensed technician with proper instruments.