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
The same code number can mean something different on another series — make sure you're reading the page for your exact unit:
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: