Rinnai Non-SENSEI Code 11
No ignition. The heater called for heat, ran its ignition sequence, and never established a flame. On this generation Rinnai's checklist starts with the gas supply and gas type, moves to the spark at the igniter and the condition and tightness of the electrode and flame rod, and then goes to inlet gas pressure, venting and combustion. A loose flame rod — what Rinnai calls a floating flame rod — will produce a code 11 or a code 12 on these units.
Call a proThe verdict
Call a licensed plumber
Almost always gas supply or the ignition assembly, and neither is a homeowner job on a gas appliance. Two checks are yours and cost nothing; everything after them is a licensed professional.
Typical cost: $150–$900
US estimate for parts and labor. Prices vary by region and by who does the work — see how we estimate costs.
What the manual says
The meaning above is transcribed from the manufacturer's diagnostic documentation for the Non-SENSEI — not averaged across the brand.
Source: Rinnai Troubleshooting Tankless Water Heater Diagnostic Codes (100000652) (p. 16), read Aug 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
Before anything else: if you smell gas, stop here, leave, and call your gas utility.
- Check that the gas is actually on: try another gas appliance, and check the meter or the propane tank gauge.
- If the unit runs on propane, confirm the tank is not low. This is the single most common cause and it costs nothing to rule out.
- Confirm the water and gas isolation valves at the unit are open — a valve closed for other work is a common cause after a plumbing visit.
- If you smell gas at any point, stop, leave the area, and call your gas utility from outside.
- If gas is present and the code stays, book a licensed professional. Do not open the unit to inspect the igniter or flame rod yourself.
Frequently asked questions
Is Rinnai code 11 the same on every model?
The fault is: no flame was established. The diagnosis differs by generation — Rinnai prints a separate checklist for Non-SENSEI units, which uses gas-type switch positions on the PC board where the SENSEI generations use software parameters.
Code 11 and code 12 keep alternating. Which is it?
Rinnai names one cause that produces both on this generation: a flame rod that has worked loose in its bracket. It is a professional inspection either way, but it is worth telling whoever comes out that you are seeing both numbers.
Code 11 on other Rinnai series
The same code number can mean something different on another series — make sure you're reading the page for your exact unit: