Noritz tankless water heater code 65
Your series decides which reading applies. Across the 3 Noritz series documented here, code 65 is listed as main flow control valve fault (2 series) and main water servo fault (1 series). Find your series in the table below, where those readings route to a replacement part.
What code 65 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| EZ Series & NCC199CDV | Main water servo fault | Part replacement | $0–$700 |
| NCC199 & NRC111 | Main flow control valve fault | Part replacement | $0–$700 |
| NR98 & NR111 | Main flow control valve fault | Part replacement | $0–$700 |
Each row opens the full page for that generation. We hold manuals for EZ Series & NCC199CDV, NCC199 & NRC111 and NR98 & NR111, and each one gets its own reading of code 65 — what Noritz documents, what you can safely check yourself, and what the repair should cost.
What each manual actually says
The table above compares 3 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 3 readings of code 65 agree and where they part company.
EZ Series & NCC199CDV — Main water servo fault
The main water servo is not functioning. This is the motorised valve that meters how much water goes through the heat exchanger, and it is how the appliance holds your set temperature at varying flow. Noritz checks that the servo is functioning and looks for an improper connection at the valve, and notes that the power has to be cycled to clear the code.
NCC199 & NRC111 — Main flow control valve fault
The main flow control valve is not functioning. Noritz checks that the valve works and looks for an improper connection, and notes that the power has to be cycled to clear the code. This is the motorised valve that meters how much water goes through the heat exchanger.
NR98 & NR111 — Main flow control valve fault
The main flow control valve is not functioning. Noritz checks that the valve works and looks for an improper connection, and notes that the power has to be cycled to clear the code. This is the motorised valve that meters how much water goes through the heat exchanger. This table pairs the main and bypass flow control valves at 65 and 66 and stops there. The NRCP ranges add a mixing valve on top of both; the EZ and NCC199CDV call the same two parts water servos. Same job, three different names across one manufacturer.
Does it matter which Noritz you have?
EZ Series & NCC199CDV, NCC199 & NRC111 and NR98 & NR111 all route code 65 the same way: a replacement part, at $0–$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 65, so they are safe to work through before you have identified your exact unit. They also cost nothing.
- Run a hot tap and see whether the code returns.
That is 1 of the 3 checks documented for code 65. 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 3 series that report code 65, the model number on the rating label starts EZ, NCC, GQ, N and NRC — match yours against the 29 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. 56), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
The same number on other brands
Code 65 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 65
Code 65 on these 3 Noritz series points at 1 guide, 2 parts and 2 symptoms, each named by the manufacturer's own procedure for this code.