Noritz tankless water heater code 72
Flame rod circuit fault. Code 72 means the same thing on all 5 Noritz series documented here — but the fix, and what it costs, is still worth reading for your exact unit.
What code 72 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| EZ Series & NCC199CDV | Flame rod circuit fault | Call a pro | $150–$700 |
| NCC199 & NRC111 | Flame rod circuit fault | Call a pro | $150–$700 |
| NR50, NR66 & NR71 | Flame rod circuit fault | Call a pro | $150–$700 |
| NR98 & NR111 | Flame rod circuit fault | Call a pro | $150–$700 |
| NRC Series | Flame rod circuit fault | Call a pro | $150–$700 |
Each row opens the full page for that generation. We hold manuals for EZ Series & NCC199CDV, NCC199 & NRC111, NR50, NR66 & NR71, NR98 & NR111 and NRC Series, and each one gets its own reading of code 72 — what Noritz documents, what you can safely check yourself, and what the repair should cost.
What each manual actually says
The table above compares 5 series in four columns, which is enough to route you and not enough to explain anything. This is the Noritz wording behind each row, one entry per manual, so you can see where the 5 readings of code 72 agree and where they part company.
EZ Series & NCC199CDV — Flame rod circuit fault
The unit believes it can see a flame when there should not be one. Noritz measures the current from the flame rod with no flame present and checks for a ground fault. It is the reverse of code 12: not failing to see a real flame, but seeing one that is not there. Unlike every other Noritz range on this site, a false flame reading here shares an appliance with a wired carbon monoxide alarm at code 13. That does not change the diagnosis, but it does change the urgency of getting it looked at rather than resetting past it.
NCC199 & NRC111 — Flame rod circuit fault
The unit is detecting a flame when there should not be one. Noritz measures the current from the flame rod with no flame present and checks for a ground fault. It is the reverse of code 12: not failing to see a real flame, but seeing one that is not there.
NR50, NR66 & NR71 — Flame rod circuit fault
The unit is detecting a flame when there should not be one. Noritz measures the current from the flame rod with no flame present and checks for a ground fault. It is the reverse of code 12: not failing to see a real flame, but seeing one that is not there. Five flashes on an NR71 or N-0631S with no remote controller. Noritz groups this with 71, 99, 70 and 73 as a five-flash fault on units with no controller, which means five flashes alone does not tell you which of them you have. That group spans a cheap flame rod and an expensive board, so it is the one flash count where getting a code read properly is worth paying for.
NR98 & NR111 — Flame rod circuit fault
The unit is detecting a flame when there should not be one. Noritz measures the current from the flame rod with no flame present and checks for a ground fault. It is the reverse of code 12: not failing to see a real flame, but seeing one that is not there. This range has no external CO alarm interlock — that is code 13 on the EZ and NCC199CDV table, and it does not exist here. A false flame signal on an NR98 or NR111 is the flame rod circuit and nothing else.
NRC Series — Flame rod circuit fault
The unit is detecting a flame when there should not be one. Noritz's procedure is to measure the current from the flame rod with no flame present and to check for a ground fault. This is the reverse of code 12: instead of failing to see a flame that is burning, the appliance believes it can see one that is not.
Does it matter which Noritz you have?
EZ Series & NCC199CDV, NCC199 & NRC111, NR50, NR66 & NR71, NR98 & NR111 and NRC Series all route code 72 the same way: a professional, at $150–$700. That makes it one of the Noritz numbers you can act on before working out which unit you own.
What to check first, whatever your series
These checks are on the manufacturer's list for every Noritz series that reports code 72, so they are safe to work through before you have identified your exact unit. They also cost nothing.
- If 72 returns, switch the unit off and leave it off.
That is 1 of the 3 checks documented for code 72. The rest differ by generation, so if none of those explains it, go to your own series above.
Which Noritz do you have?
On the 5 series that report code 72, the model number on the rating label starts EZ, NCC, GQ, N and NRC — match yours against the 43 listed below. You can also use the full model-number decoder.
Where this comes from
Source: Noritz Service Manual — NRC663 FSV, EZ98DV, EZ111DV, NCC199CDV (Rev. Oct 2017) (p. 32), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Source: Noritz Service Manual — NR50 / NR66 / NR71 / NR98 / NCC199 / NRC111 / NR111 / NC380 (Rev. July 2011) (p. 55), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
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 Noritz range.
Source: Noritz Service Manual — NR50 / NR66 / NR71 / NR98 / NCC199 / NRC111 / NR111 / NC380 (Rev. July 2011) (p. 56), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Source: Noritz Service Manual — NR501-OD, NR662-OD, NRC661, NRC711 (Rev. Dec 2013) (p. 28), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
The same number on other brands
Code 72 is not a standard across the industry — every manufacturer publishes its own table. If your unit is not a Noritz, this number means something else entirely:
Parts, guides and symptoms behind code 72
Code 72 on these 5 Noritz series points at 1 guide, 2 parts and 2 symptoms, each named by the manufacturer's own procedure for this code.