Noritz NRCP Code Er94
Exhaust overheating. The flue is too hot. Noritz gives the threshold outright: the water heater shuts down when the flue temperature exceeds 149 °F (65 °C). The remedies are a power cycle, checking whether LP gas is being supplied to a natural gas unit, and flushing the heat exchanger. That middle one is worth reading twice — Noritz treats the wrong fuel as a routine cause of a hot flue on this range.
Also displayed as: 94, E94
Call a proThe verdict
Call a licensed plumber
Two very different causes with the same symptom: a heat exchanger full of scale that is not transferring heat into the water, which a flush fixes, or the wrong fuel, which does not. The first is cheap and the second is dangerous, so this is not a code to keep resetting until you know which one you have.
Typical cost: $100–$1,200
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 — not averaged across the brand.
Source: Noritz Service Manual — NRCP111-DV / NRCP98-DV (Rev. 09/19) (p. 62), 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.
- Check the rating label on the unit against what your gas supply actually is — Noritz lists LP supplied to an NG unit as a cause.
- Note when the heat exchanger was last flushed.
- Cut the power for a minute and restore it, which is Noritz's first remedy.
- If it returns, call a licensed professional rather than resetting again.
Frequently asked questions
149 °F does not sound hot for an exhaust. Is that right?
It is, and it is the point. This is a condensing appliance: it is designed to pull so much heat out of the flue gas that the water vapour in it condenses, which is why it has a condensate drain at all. A flue running above 149 °F means that heat is going up the vent instead of into your water — most often because the heat exchanger is scaled.
Code Er94 on other Noritz series
Other Noritz series report code Er94 under the same fault name, but each manual is transcribed separately and they do not read alike:
Don't confuse this with
2 other Noritz NRCP codes point at the exhaust path 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: