Ruud · Water heater
Code 11 Ignition failure
What this code means
Ruud is a Rheem sister brand sharing the same tankless platform and code numbering — the unit failed to establish a flame on startup.
Most likely causes
- Gas supply valve not fully open
- Low incoming gas pressure
- Igniter or flame rod fault
What to try first
Confirm the gas shutoff valve at the unit is fully open and the vent termination outside is unobstructed.
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 Ruud error code Code 11 mean?
Ignition failure. Ruud is a Rheem sister brand sharing the same tankless platform and code numbering — the unit failed to establish a flame on startup.
Can I fix Ruud code Code 11 myself?
Usually not. Confirm the gas shutoff valve at the unit is fully open and the vent termination outside is unobstructed. If the code returns after one reset, it needs a licensed technician.
What causes Ruud code Code 11?
The most common causes are: gas supply valve not fully open; low incoming gas pressure; igniter or flame rod fault.
Other Ruud water heater codes
All Ruud water heater error codes →
Other water heater brands: Rheem · Rinnai · 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.