Noritz error code 20
It depends on your series. Code 20 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 20 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| EZ Series & NCC199CDV | Heat exchanger high limit switch triggered | Call a pro | $100–$900 |
| NCC199 & NRC111 | High limit switch triggered | Call a pro | $150–$900 |
| NR50, NR66 & NR71 | High limit switch triggered | Call a pro | $150–$900 |
| NR98 & NR111 | High limit switch triggered | Call a pro | $150–$900 |
| NRC Series | High limit switch triggered | Call a pro | $150–$900 |
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 20 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 cost is documented the same way across all 5 series: $100–$900, depending on which of the manufacturer's causes turns out to be yours.
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. 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.
Parts, guides and symptoms behind code 20
Everything the 5 Noritz series point at for this code, in one list. A part named here is one the manufacturer's own procedure reaches for.