Noritz tankless water heater code 99
Your series decides which reading applies. Across the 4 Noritz series documented here, code 99 is listed as combustion fault, unit shuts off (3 series) and combustion fault, unit locked (1 series). Find your series in the table below, where those readings route to a professional.
What code 99 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NCC199 & NRC111 | Combustion fault, unit shuts off | Call a pro | $0–$1,000 |
| NR50, NR66 & NR71 | Combustion fault, unit shuts off | Call a pro | $0–$1,000 |
| NR98 & NR111 | Combustion fault, unit shuts off | Call a pro | $0–$1,000 |
| NRC Series | Combustion fault, unit locked | Call a pro | $200–$1,200 |
Each row opens the full page for that generation. We hold manuals for NCC199 & NRC111, NR50, NR66 & NR71, NR98 & NR111 and NRC Series, and each one gets its own reading of code 99 — 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 99 agree and where they part company.
NCC199 & NRC111 — Combustion fault, unit shuts off
Combustion abnormality with the unit stopped. Noritz's checks are abnormal combustion and the flue for blockage or obstruction, and the power has to be cycled to clear it.
NR50, NR66 & NR71 — Combustion fault, unit shuts off
Combustion abnormality with the unit stopped. Noritz's checks are abnormal combustion and the flue for blockage or obstruction, and the power has to be cycled to clear it. Five flashes on an NR71 or N-0631S with no remote controller. Noritz gives 90 and 99 the same two checks on this table and separates them only by whether the unit stopped. On a unit with no controller both live in different flash groups — 90 flashes continuously, 99 is one of the five-flash faults — so the light tells you more here than the checklist does.
NR98 & NR111 — Combustion fault, unit shuts off
Combustion abnormality with the unit stopped. Noritz's checks are abnormal combustion and the flue for blockage or obstruction, and the power has to be cycled to clear it. The difference from 90 on this table is that the unit has stopped. Noritz gives both the same two checks — abnormal combustion, and the flue for blockage — so what tells you which one you are dealing with is whether you still have hot water, not the checklist.
NRC Series — Combustion fault, unit locked
Combustion abnormality with the unit locked out. Noritz's checks are abnormal combustion and the flue for blockage or obstruction, and the remark is unambiguous: to reset this error code, contact the nearest Noritz agent. Unlike the 90x family, cycling the power will not clear it.
How much the answer changes between series
NCC199 & NRC111, NR50, NR66 & NR71, NR98 & NR111 and NRC Series all route code 99 the same way: a professional, at $0–$1,200. That makes it one of the Noritz numbers you can act on before working out which unit you own.
The spread is real money. On the NCC199 & NRC111 the worst case is $1,000; on the NRC Series the same number can reach $1,200. That is a $200 gap behind one number.
Which Noritz do you have?
On the 4 series that report code 99, the model number on the rating label starts NCC, N, NRC, NR and NC — match yours against the 37 listed below. You can also use the full model-number decoder.
Where this comes from
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. 54), 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 99 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 99
Code 99 on these 4 Noritz series points at 2 parts and 2 symptoms, each named by the manufacturer's own procedure for this code.