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