Noritz tankless water heater code 94
Exhaust temperature too high. Code 94 means the same thing on all 2 Noritz series documented here — but the fix, and what it costs, is still worth reading for your exact unit.
What code 94 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| EZ Series & NCC199CDV | Exhaust temperature too high | Call a pro | $200–$1,000 |
| NRC Series | Exhaust temperature too high | Call a pro | $200–$1,000 |
Each row opens the full page for that generation. We hold manuals for EZ Series & NCC199CDV and NRC Series, and each one gets its own reading of code 94 — what Noritz documents, what you can safely check yourself, and what the repair should cost.
What each manual actually says
The table above compares 2 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 2 readings of code 94 agree and where they part company.
EZ Series & NCC199CDV — Exhaust temperature too high
The flue is running hotter than it should. Noritz's check is a single line — check for abnormal combustion, pointing at the exhaust thermistor — and the remark is that power must be cycled to clear it.
NRC Series — Exhaust temperature too high
The flue is running hotter than it should. Noritz's check is a single line — check for abnormal combustion — pointing at the exhaust thermistor as the input. The 2017 service manual for the NRC663-FSV labels the two display-window codes explicitly, 941 as a warning indication and 942 as the unit shutting off; the 2013 manual prints the same two numbers without those labels. Below both sits a locked state that Noritz says requires a Noritz agent to clear.
Does it matter which Noritz you have?
EZ Series & NCC199CDV and NRC Series all route code 94 the same way: a professional, at $200–$1,000. 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 2 series that report code 94, the model number on the rating label starts EZ, NCC, GQ, NRC and NR — match yours against the 13 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 — NR501-OD, NR662-OD, NRC661, NRC711 (Rev. Dec 2013) (p. 28), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Parts, guides and symptoms behind code 94
Code 94 on these 2 Noritz series points at 2 guides, 2 parts and 2 symptoms, each named by the manufacturer's own procedure for this code.