Noritz EZ Series & NCC199CDV Code 30
Air thermistor fault. The air temperature sensor is out of range. Noritz measures its resistance, checks for an open or short circuit, and checks the connection. The air sensor is component 17 in this table's diagram, where the NCC199 and NRC111 table numbers its equivalent 19 and the NR98 range numbers it 29. Three Noritz tables, three reference numbers for the same measurement — worth stating before a technician works from the wrong page.
Also displayed as: F30
Part replacementThe verdict
Replace a part
Inexpensive sensor, quick job, but inside the cabinet of a gas appliance so it is a service call. Nothing about the fault is dangerous — the unit has lost one of its inputs.
Typical cost: $120–$400
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
- Book a service call. Noritz lists no homeowner check for this code.
Code 30 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: