Rinnai Tankless Water Heater 11 — No Ignition
Rinnai Tankless Water Heater · Error code 11
What 11 Means
The unit attempted to ignite but failed to detect a flame within the trial-for-ignition period. Most common Rinnai fault code.
Symptoms
- No hot water
- Click or fan but no burner
- Code 11 immediately on hot water demand
Common Causes
Closed valve, empty propane tank, or undersized gas line.
Common after new installation or tank refill.
Inlet pressure outside spec (NG ~7" WC, LP ~11" WC static).
Cracked ceramic igniter or carbon-fouled flame sensor.
Valve not opening on command.
Board not commanding ignition sequence.
How to Fix It
- Verify gas valve to unit is fully open and other gas appliances work.
- For propane, confirm tank has fuel and regulator isn't iced.
- Purge air: run a stove burner or other gas appliance for a few minutes.
- Power-cycle the unit and try a hot tap.
- Remove front cover and inspect the igniter and flame rod — clean flame rod with fine sandpaper.
- Have a tech measure inlet gas pressure at the unit, static and dynamic.
- Replace igniter, flame rod, or gas solenoid based on findings.
Parts You May Need
If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.
More Rinnai Tankless Water Heater Codes
Verified against manufacturer documentation: rinnai.us
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.