Noritz tankless water heater code 30
Your series decides which reading applies. Across the 4 Noritz series documented here, code 30 is listed as air thermistor fault (2 series) and air inlet thermistor fault (2 series). Find your series in the table below, where those readings route to a replacement part.
What code 30 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| EZ Series & NCC199CDV | Air thermistor fault | Part replacement | $120–$400 |
| NCC199 & NRC111 | Air inlet thermistor fault | Part replacement | $120–$400 |
| NR98 & NR111 | Air inlet thermistor fault | Part replacement | $120–$400 |
| NRC Series | Air thermistor fault | Part replacement | $120–$400 |
Each row opens the full page for that generation. We hold manuals for EZ Series & NCC199CDV, NCC199 & NRC111, NR98 & NR111 and NRC Series, and each one gets its own reading of code 30 — what Noritz documents, what you can safely check yourself, and what the repair should cost.
What each manual actually says
The table above compares 4 series in four columns, which is enough to route you and not enough to explain anything. This is the Noritz wording behind each row, one entry per manual, so you can see where the 4 readings of code 30 agree and where they part company.
EZ Series & NCC199CDV — 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.
NCC199 & NRC111 — Air inlet thermistor fault
The sensor reading incoming air temperature is out of range. Noritz measures its resistance, checks for an open or short circuit, and checks its connection.
NR98 & NR111 — Air inlet thermistor fault
The sensor reading incoming air temperature is out of range. Noritz measures its resistance, checks for an open or short circuit, and checks its connection. Noritz references this sensor as component 29 in the p. 56 table's diagram, where the NCC199 and NRC111 table numbers the same sensor 19. If a technician is working from the wrong page the reference will not match what they find.
NRC Series — Air thermistor fault
The sensor reading the incoming air temperature is out of range. Noritz's procedure is to measure its resistance and check the connection, looking specifically for an open circuit or a short — the two display-window codes separate those cases for a technician.
Does it matter which Noritz you have?
EZ Series & NCC199CDV, NCC199 & NRC111, NR98 & NR111 and NRC Series all route code 30 the same way: a replacement part, at $120–$400. That makes it one of the Noritz numbers you can act on before working out which unit you own.
Which Noritz do you have?
On the 4 series that report code 30, the model number on the rating label starts EZ, NCC, GQ, N and NRC — match yours against the 36 listed below. You can also use the full model-number decoder.
Where this comes from
Source: Noritz Service Manual — NRC663 FSV, EZ98DV, EZ111DV, NCC199CDV (Rev. Oct 2017) (p. 32), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Source: Noritz Service Manual — NR50 / NR66 / NR71 / NR98 / NCC199 / NRC111 / NR111 / NC380 (Rev. July 2011) (p. 55), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Source: Noritz Service Manual — NR50 / NR66 / NR71 / NR98 / NCC199 / NRC111 / NR111 / NC380 (Rev. July 2011) (p. 56), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Source: Noritz Service Manual — NR501-OD, NR662-OD, NRC661, NRC711 (Rev. Dec 2013) (p. 28), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
The same number on other brands
Code 30 is not a standard across the industry — every manufacturer publishes its own table. If your unit is not a Noritz, this number means something else entirely:
Parts, guides and symptoms behind code 30
Code 30 on these 4 Noritz series points at 1 part and 1 symptom, each named by the manufacturer's own procedure for this code.