Noritz tankless water heater code Er94
Exhaust overheating. Code Er94 means the same thing on all 2 Noritz series documented here — but the fix, and what it costs, is still worth reading for your exact unit.
What code Er94 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NRCP | Exhaust overheating | Call a pro | $100–$1,200 |
| NRCP Eco TOUGH | Exhaust overheating | Call a pro | $0–$1,000 |
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 Er94 — 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 Er94 agree and where they part company.
NRCP — 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.
NRCP Eco TOUGH — Exhaust overheating
The flue is too hot. Noritz's remedies on this generation are to turn the water heater off for at least thirty minutes and restart it, clean the cold water inlet filter, and flush the heat exchanger. The first-generation manual instead names LP gas supplied to a natural gas unit as a cause and states the shutdown threshold of 149 °F; neither appears here. Manual reset.
How much the answer changes between series
NRCP and NRCP Eco TOUGH all route code Er94 the same way: a professional, at $0–$1,200. That makes it one of the Noritz numbers you can act on before working out which unit you own.
The spread is real money. On the NRCP Eco TOUGH the worst case is $1,000; on the NRCP the same number can reach $1,200. That is a $200 gap behind one number.
Which Noritz do you have?
On the 2 series that report code Er94, 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 Er94
Code Er94 on these 2 Noritz series points at 3 guides, 4 parts and 2 symptoms, each named by the manufacturer's own procedure for this code.