Rinnai · Water heater
Code 12 Flame failure during operation
What this code means
Flame was established but dropped out during a hot water draw.
Most likely causes
- Dirty flame rod
- Unstable gas pressure
- Debris in the burner chamber
What to try first
This needs the burner compartment opened for inspection — a job for a licensed technician given the gas components involved.
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 Rinnai error code Code 12 mean?
Flame failure during operation. Flame was established but dropped out during a hot water draw.
Can I fix Rinnai code Code 12 myself?
Usually not. This needs the burner compartment opened for inspection — a job for a licensed technician given the gas components involved. If the code returns after one reset, it needs a licensed technician.
What causes Rinnai code Code 12?
The most common causes are: dirty flame rod; unstable gas pressure; debris in the burner chamber.
Other Rinnai water heater codes
All Rinnai water heater error codes →
Other water heater brands: Rheem · Ruud · Navien · Noritz · 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.