Noritz tankless water heater code Er72
Your series decides which reading applies. Across the 2 Noritz series documented here, code Er72 is listed as flame detected before the gas valve opens (1 series) and flame detected before ignition (1 series). Find your series in the table below, where those readings route to a professional.
What code Er72 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NRCP | Flame detected before the gas valve opens | Call a pro | $0–$700 |
| NRCP Eco TOUGH | Flame detected before ignition | Call a pro | $100–$700 |
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 Er72 — 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 Er72 agree and where they part company.
NRCP — Flame detected before the gas valve opens
The unit saw a flame signal before it had opened the gas valve. Noritz's remedies are to make sure the front cover is closed securely and to check the flame sensor voltage, which should be 5 VDC with no flame — the same pair it gives for Er39, at the other end of the firing cycle.
NRCP Eco TOUGH — Flame detected before ignition
The unit saw a flame signal before it should have. Noritz's remedies are to measure the current from the flame sensor when there is no flame, and notes that the power has to be disconnected and reconnected to clear the code. Auto reset in the reset column, with that manual instruction alongside it.
Does it matter which Noritz you have?
NRCP and NRCP Eco TOUGH all route code Er72 the same way: a professional, at $0–$700. That makes it one of the Noritz numbers you can act on before working out which unit you own.
Which Noritz do you have?
On the 2 series that report code Er72, 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 Er72
Code Er72 on these 2 Noritz series points at 2 parts and 2 symptoms, each named by the manufacturer's own procedure for this code.