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
Other Noritz series report code 16 under the same fault name, but each manual is transcribed separately and they do not read alike: