Noritz · Water heater
Code 10 Flame failure / flame loss
What this code means
The unit lost its flame in the combustion chamber after ignition.
Most likely causes
- Unstable or low gas pressure
- Dirty flame sensor rod
- Debris in the burner assembly
What to try first
Confirm the gas shutoff valve is fully open; beyond that this needs the burner compartment opened.
Safety note: if this code returns after one clean reset, stop resetting it — repeated lockouts usually mean a real fault that needs a licensed technician. Never bypass a safety switch.
FAQ
What does Noritz error code Code 10 mean?
Flame failure / flame loss. The unit lost its flame in the combustion chamber after ignition.
Can I fix Noritz code Code 10 myself?
Usually not. Confirm the gas shutoff valve is fully open; beyond that this needs the burner compartment opened. If the code returns after one reset, it needs a licensed technician.
What causes Noritz code Code 10?
The most common causes are: unstable or low gas pressure; dirty flame sensor rod; debris in the burner assembly.
Other Noritz water heater codes
All Noritz water heater error codes →
Other water heater brands: Rheem · Ruud · Rinnai · Navien · Takagi · A.O. Smith · Bradford White · State / American · Generic electric · Generic tankless
This information may contain errors or not apply to your exact model — always double-check it against your appliance's own manual before acting. If there's any chance of a gas, fire, electrical, carbon monoxide, or other safety hazard, stop and call a licensed professional or the appropriate agency (e.g. your gas utility) instead of relying on this page alone.