Noritz NR50, NR66 & NR71 Code 14
Thermal fuse triggered. The thermal fuse has opened. Noritz checks the fuse 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. On an NR71 or N-0631S with no remote controller this is four flashes.
Also displayed as: 4 flashes
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.
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 NR50, NR66 & NR71 — not averaged across the brand.
Source: Noritz Service Manual — NR50 / NR66 / NR71 / NR98 / NCC199 / NRC111 / NR111 / NC380 (Rev. July 2011) (p. 54), 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.
- Leave the unit off and call a licensed professional. Do not fit a fuse and carry on.
Code 14 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: