Noritz NRC Series Code 14
Thermal fuse triggered. The overheat prevention device — a thermal fuse — has opened and cut the unit off. Noritz's checks are the fuse itself, for melting or damage, and its connection. A thermal fuse is a one-shot part: it does not reset, and it opened because something made the appliance hot enough to need it.
Call a proThe verdict
Call a licensed plumber
Fitting a new fuse without finding what overheated the unit just re-arms the same fault, usually within days. The cause is normally restricted air flow or a heat exchanger full of scale, and both cost more to ignore than to fix.
Typical cost: $200–$1,200
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 NRC Series — not averaged across the brand.
Source: Noritz Service Manual — NR501-OD, NR662-OD, NRC661, NRC711 (Rev. Dec 2013) (p. 28), 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.
- Check nothing has been stacked against the heater or its vent terminal.
- Note when the unit was last flushed — scale in the heat exchanger is a common route to this fault.
- Leave the unit off and call a licensed professional. Do not fit a fuse and carry on.
Code 14 on other Noritz series
Other Noritz series report code 14 under the same fault name, but each manual is transcribed separately and they do not read alike: