Boiler will not ignite; display shows error 11 shortly after a call for heat or hot water.

Safety first: Turn OFF power to the boiler at the breaker and close the gas shutoff valve before removing covers. If you ever smell gas, stop immediately and contact your gas supplier or a licensed technician.

• 1. Reset and verify demand: Restore power, reset the unit, and confirm there is an actual call for heat or hot water. Make sure gas valves to the Noritz boiler are fully open.
• 2. Check gas supply: Verify other gas appliances (stove, furnace) work. If they do not, the issue may be with the gas supply line or utility. Do not attempt to adjust the gas meter or main regulator yourself.
• 3. Inspect igniter and flame rod: With power and gas OFF, remove the front cover. Locate the igniter and flame rod assembly near the burner. Look for cracks, heavy carbon buildup, or loose wiring. Clean light deposits with a soft brush and reinstall firmly. Replace the assembly if cracked or heavily corroded.
• 4. Check burner area: Inspect the burner surface for debris, rust flakes, or insect nests. Gently vacuum or brush away loose material without damaging the burner ports.
• 5. Restore and test: Turn gas and power back ON, then run hot water or call for heat. If error 11 returns repeatedly, stop using the boiler and schedule a qualified Noritz technician to check gas pressure and combustion settings.