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
The same code number can mean something different on another series — make sure you're reading the page for your exact unit:
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: