Noritz NCC199 & NRC111 Code 16
Abnormally high output temperature. The water leaving the unit is too hot. Noritz measures the resistance of the outlet thermistor and then checks the gas proportioning valve — one cause is a measurement problem, the other is the appliance really overfiring.
Also displayed as: F16
Call a proThe verdict
Call a licensed plumber
Turn the temperature down and treat scalding as a live risk until someone has looked. A gas proportioning valve fault is combustion work and needs instruments, so the diagnosis is not a homeowner job even though the symptom is obvious.
Typical cost: $200–$900
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 NCC199 & NRC111 — not averaged across the brand.
Source: Noritz Service Manual — NR50 / NR66 / NR71 / NR98 / NCC199 / NRC111 / NR111 / NC380 (Rev. July 2011) (p. 55), 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.
- Turn the set temperature down at the controller and warn the household before anyone runs a tap.
- Call a licensed professional.
Code 16 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: