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