Noritz EZ Series & NCC199CDV Code 35
Exhaust thermistor fault. The sensor in the exhaust is out of range. Noritz measures its resistance, checks for an open or short circuit, and checks the connection — the same procedure as the other thermistors. What makes it different is its position: in the flue, where the appliance watches for an exhaust temperature that says combustion has gone wrong.
Also displayed as: F35
Call a proThe verdict
Call a licensed plumber
The part costs the same as the other thermistors, but while it is unreliable the unit has lost the input behind code 94. 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 EZ Series & NCC199CDV — not averaged across the brand.
Source: Noritz Service Manual — NRC663 FSV, EZ98DV, EZ111DV, NCC199CDV (Rev. Oct 2017) (p. 32), 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 35 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
5 other Noritz EZ Series & NCC199CDV 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: