Noritz tankless water heater code Er33
Heat exchanger thermistor open or short. Code Er33 means the same thing on all 2 Noritz series documented here — but the fix, and what it costs, is still worth reading for your exact unit.
What code Er33 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NRCP | Heat exchanger thermistor open or short | Part replacement | $120–$450 |
| NRCP Eco TOUGH | Heat exchanger thermistor open or short | Part replacement | $120–$450 |
Each row opens the full page for that generation. We hold manuals for NRCP and NRCP Eco TOUGH, and each one gets its own reading of code Er33 — what Noritz documents, what you can safely check yourself, and what the repair should cost.
What each manual actually says
The table above compares 2 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 2 readings of code Er33 agree and where they part company.
NRCP — Heat exchanger thermistor open or short
The heat exchanger sensor is open circuit or short circuit, with the same shared remedies: sensor and connectors, resistance, replacement.
NRCP Eco TOUGH — Heat exchanger thermistor open or short
The heat exchanger sensor is open or short circuit, with the same shared remedies and the same auto reset. The reset column is the difference from the first generation. Noritz marks this one auto reset here; the NRCP111 and NRCP98 table has no reset column at all, so on that generation you are not told whether to expect the code to clear itself.
Does it matter which Noritz you have?
NRCP and NRCP Eco TOUGH all route code Er33 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 Er33, so they are safe to work through before you have identified your exact unit. They also cost nothing.
- Ask the technician to check the heat exchanger for scale while it is open.
- Book a service call.
That is 2 of the 2 checks documented for code Er33. 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 2 series that report code Er33, the model number on the rating label starts NRCP — match yours against the 4 listed below. You can also use the full model-number decoder.
Where this comes from
Source: Noritz Service Manual — NRCP111-DV / NRCP98-DV (Rev. 09/19) (p. 62), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Source: Noritz Service Manual — NRCP1112-DV / NRCP982-DV Eco TOUGH (Rev. 05/19) (p. 58), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Parts, guides and symptoms behind code Er33
Code Er33 on these 2 Noritz series points at 1 guide, 2 parts and 1 symptom, each named by the manufacturer's own procedure for this code.