Noritz NRCP Code Er33
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.
Also displayed as: 33, E33
Part replacementThe verdict
Replace a part
Cheap sensor, service call to reach it. Ask about scale while the unit is open — a sensor sitting on a furred heat exchanger reads late even when it is healthy.
Typical cost: $120–$450
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 NRCP — not averaged across the brand.
Source: Noritz Service Manual — NRCP111-DV / NRCP98-DV (Rev. 09/19) (p. 62), read Sep 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
- Ask the technician to check the heat exchanger for scale while it is open.
- Book a service call.
Code Er33 on other Noritz series
Other Noritz series report code Er33 under the same fault name, but each manual is transcribed separately and they do not read alike:
Don't confuse this with
3 other Noritz NRCP codes point at a thermistor too. They are different components in different places, and ordering a part against the wrong one is the most common way this fault gets expensive: