Noritz NRCP Code Er35
Exhaust thermistor open or short. The exhaust sensor is open circuit or short circuit. Noritz gives it the same remedies as the water-side thermistors, but its position makes it a different proposition: it sits in the flue, and it is the input behind Er94, the exhaust overheating code.
Also displayed as: 35, E35
Call a proThe verdict
Call a licensed plumber
The part costs what the other thermistors cost. The difference is that while it is open or shorted, the unit has lost its ability to notice a flue running too hot. Have it done rather than deferred.
Typical cost: $150–$500
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
Before anything else: if you smell gas, stop here, leave, and call your gas utility.
- Call a licensed professional. The sensor is in the exhaust stream and the work around it is combustion work.
Code Er35 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: