Noritz error code 21
It depends on your series. Code 21 does not point at the same fault on every Noritz unit. Find your series in the table below before you buy a part or book anyone.
What code 21 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| EZ Series & NCC199CDV | Burner chamber high limit switch triggered | Call a pro | $250–$1,500 |
| NR98 & NR111 | Pressure switch triggered | Call a pro | $200–$1,200 |
Each series links to the full page: what the manufacturer's manual says for that generation, what you can safely check yourself, and what the repair should cost.
How much the answer changes between series
Every Noritz series that documents code 21 routes it the same way: a professional. That is unusual enough to be worth saying, because on this brand the same number often means different work on different generations. Here it does not — so you can act on this page without first establishing which unit you own.
The spread is real money. On the NR98 & NR111 the worst case is $1,200; on the EZ Series & NCC199CDV the same number can reach $1,500. Identify your series before you agree to anything.
Which Noritz do you have?
The model number is on the rating label on the unit itself. Match it against the list below — or 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. 56), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
The same number on other brands
Code 21 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 21
Everything the 2 Noritz series point at for this code, in one list. A part named here is one the manufacturer's own procedure reaches for.