Noritz NRCP Eco TOUGH Code Er16
Overheating. The heat exchanger and hot water temperature sensors are reporting an overheat. Noritz's first remedy on this generation is distinctive: turn the water heater off for at least thirty minutes and then restart it. After that, clean the cold water inlet filter and the recirculation return filter, and flush the heat exchanger. Noritz marks it auto reset, so the unit will clear the code itself once conditions allow.
Also displayed as: 16, E16
DIY fixThe verdict
Descale the unit
Thirty minutes off, then two filters, then a flush — in that order, because that is the order the manufacturer gives. The wait is not arbitrary: it lets whatever is holding heat in the exchanger dissipate before the unit fires again.
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 Eco TOUGH — not averaged across the brand.
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 exact series.
What you can safely check
- Turn the water heater off and leave it off for at least thirty minutes. Noritz asks for the full half hour, not a quick power cycle.
- Restart it and see whether Er16 returns.
- Clean the cold water inlet filter and the recirculation return filter — this unit has both, and the return one is the one people forget.
- Flush the heat exchanger if it keeps coming back.
- If none of that clears it, book a service call.
Frequently asked questions
Why thirty minutes and not just a power cycle?
Because an overheat code is about heat that is still in the appliance. A quick off-and-on returns the unit to a heat exchanger that is still hot, and it trips again. Noritz asks for thirty minutes so the thermal mass actually cools. The first-generation NRCP manual does not include this step, which is one of the differences between the two tables.
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: