Furnace makes loud booming or delayed ignition noise when burners light.

Warning: Delayed ignition can damage the heat exchanger and pose a safety risk. If the boom is severe, shut down the furnace and call a professional.

• Step 1 – Inspect burners: With power and gas off, remove burners and clean with a brush and compressed air. Ensure crossover ports are clear.
• Step 2 – Check ignitor position: Verify the hot surface ignitor is properly aligned with the burner it lights. Adjust mounting if necessary.
• Step 3 – Replace weak ignitor: If the ignitor glows dimly or slowly, replace it with the correct Tempstar part.
• Step 4 – Professional gas adjustment: Have a licensed technician check and adjust gas pressure and combustion.