Noritz tankless water heater code 33
Your series decides which reading applies. Across the 4 Noritz series documented here, code 33 is listed as heat exchanger thermistor fault (3 series) and heat exchanger outlet thermistor fault (1 series). Find your series in the table below, where those readings route to a replacement part.
What code 33 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| EZ Series & NCC199CDV | Heat exchanger outlet thermistor fault | Part replacement | $120–$450 |
| NCC199 & NRC111 | Heat exchanger thermistor fault | Part replacement | $120–$450 |
| NR98 & NR111 | Heat exchanger thermistor fault | Part replacement | $120–$450 |
| NRC Series | Heat exchanger thermistor fault | Part replacement | $120–$450 |
Each row opens the full page for that generation. We hold manuals for EZ Series & NCC199CDV, NCC199 & NRC111, NR98 & NR111 and NRC Series, and each one gets its own reading of code 33 — what Noritz documents, what you can safely check yourself, and what the repair should cost.
What each manual actually says
The table above compares 4 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 4 readings of code 33 agree and where they part company.
EZ Series & NCC199CDV — Heat exchanger outlet thermistor fault
The sensor on the outlet of the primary heat exchanger is out of range. Noritz measures its resistance, checks for an open or short circuit, and checks the connection. This series has thermistors on both the inlet and the outlet of the heat exchanger — 36 and 33 — and they are different parts in different places.
NCC199 & NRC111 — Heat exchanger thermistor fault
The heat exchanger sensor is out of range. Noritz measures its resistance, checks for an open or short circuit, and checks the connection.
NR98 & NR111 — Heat exchanger thermistor fault
The heat exchanger sensor is out of range. Noritz measures its resistance, checks for an open or short circuit, and checks the connection. This range has one heat exchanger thermistor. The EZ and NCC199CDV range has two — an inlet at 36 and an outlet at 33 — so a code 33 page written for those models is describing a different sensor position on a different appliance.
NRC Series — Heat exchanger thermistor fault
The sensor on the heat exchanger is out of range. Noritz checks resistance and connection, with the display-window codes separating an open circuit from a short. This is the sensor that lets the unit see what the heat exchanger itself is doing, as distinct from the water leaving it.
Does it matter which Noritz you have?
EZ Series & NCC199CDV, NCC199 & NRC111, NR98 & NR111 and NRC Series all route code 33 the same way: a replacement part, at $120–$450. 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 33, so they are safe to work through before you have identified your exact unit. They also cost nothing.
- Book a service call.
That is 1 of the 3 checks documented for code 33. 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 4 series that report code 33, the model number on the rating label starts EZ, NCC, GQ, N and NRC — match yours against the 36 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.
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 33 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 33
Code 33 on these 4 Noritz series points at 1 guide, 2 parts and 1 symptom, each named by the manufacturer's own procedure for this code.