Noritz NRCP Eco TOUGH Code Er73
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.
Also displayed as: 73, E73
Call a proThe verdict
Call a licensed plumber
This usually appears right after someone has been inside the unit or replaced a board. The switches are combustion settings rather than preferences, so correcting them is professional work even though the physical act is flicking a switch.
Typical cost: $100–$600
US estimate for parts and labor. Prices vary by region and by who does the work — see how we estimate costs.
What the manual says
The meaning above is transcribed from the manufacturer's diagnostic documentation for the NRCP Eco TOUGH — not averaged across the brand.
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 exact series.
What you can safely check
Before anything else: if you smell gas, stop here, leave, and call your gas utility.
- 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.
Code Er73 on other Noritz series
Other Noritz series report code Er73 under the same fault name, but each manual is transcribed separately and they do not read alike:
Don't confuse this with
3 other Noritz NRCP Eco TOUGH codes point at a switch too. They are different components in different places, and ordering a part against the wrong one is the most common way this fault gets expensive: