Noritz NRCP Code Er16
Overheating. The heat exchanger and hot water temperature sensors are reporting an overheat. Every remedy Noritz gives for this code is maintenance you can do: switch the main power off and on, clean the cold water inlet filter and the recirculation return filter, and flush the heat exchanger. That is a manufacturer telling you the usual cause is restricted flow or scale rather than a failed part.
Also displayed as: 16, E16
DIY fixThe verdict
Descale the unit
Two filters and a flush, and Noritz lists nothing else. On a recirculating unit the return filter is the one people forget exists, and it is the one most likely to be blocked. If the code survives all three, then it is a service call.
Typical cost: $0–$400
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
- Cut the power for a minute and restore it — Noritz's first remedy.
- Clean the cold water inlet filter.
- Clean the recirculation return filter as well. This unit has two, and the return one is the one that gets forgotten.
- Flush the heat exchanger if the code returns.
- If Er16 is still there after all three, book a service call.
Code Er16 on other Noritz series
Other Noritz series report code Er16 under the same fault name, but each manual is transcribed separately and they do not read alike:
Don't confuse this with
One other Noritz NRCP code points at overheating too. They are the same symptom reported from a different place in the unit, so which one the display shows is what tells you where to look: