Noritz NR50, NR66 & NR71 Code 11
Ignition failure. The burner never lit — Noritz calls it initial flame fault detection. The checklist is gas supply piping and pressure, igniter spark, the gas solenoid valves, the flame rod, and the ground connection at the circuit board, which Noritz singles out because flame detection depends on a good earth. On an NR71 or N-0631S with no remote controller, this is one of the continuous flashing faults. This is the shortest table on the site — seventeen codes — and that shapes the diagnosis. There is no separate air pressure switch code and no multi-system code to eliminate, so an ignition failure here is gas, spark and earth, with nothing else competing for the explanation.
Also displayed as: continuous flashing
Call a proThe verdict
Call a licensed plumber
Check the gas is on, which is free. Everything after that is spark, solenoid valves and manifold pressure, and needs a technician. Do not keep resetting — each attempt puts unburned gas into a combustion chamber.
Typical cost: $0–$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 NR50, NR66 & NR71 — not averaged across the brand.
Source: Noritz Service Manual — NR50 / NR66 / NR71 / NR98 / NCC199 / NRC111 / NR111 / NC380 (Rev. July 2011) (p. 54), read Sep 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 the gas is on at the heater's valve and at the meter, and on propane that the tank is not empty.
- Try another gas appliance — if nothing gas-fired works, the supply is the problem.
- If any gas work was done in the house recently, say so when you book.
- Call a licensed professional rather than repeating the reset.
Code 11 on other Noritz series
The same code number can mean something different on another series — make sure you're reading the page for your exact unit: