Noritz tankless water heater code Er73
DIP switch setting fault. Code Er73 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 Er73 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NRCP | DIP switch setting fault | Call a pro | $100–$600 |
| NRCP Eco TOUGH | DIP switch setting fault | Call a pro | $100–$600 |
Each row opens the full page for that generation. We hold manuals for NRCP and NRCP Eco TOUGH, and each one gets its own reading of code Er73 — 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 Er73 agree and where they part company.
NRCP — DIP switch setting fault
The DIP switch settings on the board are wrong or inconsistent. Noritz's remedy is one line — check the DIP switch settings. On a condensing appliance these encode things like vent configuration and elevation, which determine how it burns gas.
NRCP Eco TOUGH — DIP switch setting fault
The DIP switch settings on the board are wrong or inconsistent. Noritz's remedy is one line — check the DIP switch settings. On a condensing appliance these encode vent configuration and elevation, which determine how it burns gas. Auto reset. Auto reset here, and the first-generation table does not say. That is the single most useful thing the Eco TOUGH manual adds over its predecessor: for every code it states whether the unit clears it or waits for you, which is the first question anyone standing in front of it actually has.
Does it matter which Noritz you have?
NRCP and NRCP Eco TOUGH all route code Er73 the same way: a professional, at $100–$600. That makes it one of the Noritz numbers you can act on before working out which unit you own.
What to check first, whatever your series
These checks are on the manufacturer's list for every Noritz series that reports code Er73, so they are safe to work through before you have identified your exact unit. They also cost nothing.
- Think back to any recent work on the heater or its venting and mention it when you book.
- Do not open the unit to change switch positions yourself.
- Call a licensed professional.
That is 3 of the 3 checks documented for code Er73. The rest differ by generation, so if none of those explains it, go to your own series above.
Which Noritz do you have?
On the 2 series that report code Er73, the model number on the rating label starts NRCP — match yours against the 4 listed below. You can also use the full model-number decoder.
Where this comes from
Source: Noritz Service Manual — NRCP111-DV / NRCP98-DV (Rev. 09/19) (p. 62), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Source: Noritz Service Manual — NRCP1112-DV / NRCP982-DV Eco TOUGH (Rev. 05/19) (p. 58), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Parts, guides and symptoms behind code Er73
Code Er73 on these 2 Noritz series points at 1 part and 2 symptoms, each named by the manufacturer's own procedure for this code.