If you own a Noritz tankless water heater and see an Error Code 14 on the remote or main display, STOP and call for service. Do not attempt to repair as a DIY project.
The error code warns the user of an overheating condition at the heat exchanger.
The most common reason for Error Code 14: Scale build-up.
Although I don’t recommend you repair the heat exchanger, removing scale build-up is a job you can perform. However, the heater must have insolation valves installed. I’ve circled them in red.
The valves don’t ship with the new heater out of the box because not all water service needs to be cleaned. Since the valves are primarily used to descale the heat exchanger, they’re considered an additional purchase. If you’re having a home built in an area where the water has a high mineral content, you’ll want to confirm the builder/plumber includes the valves in your installation.
Learn more about the error code and descaling the appliance in this short Tech Tip video. And keep scrolling for the video on how to descale your tankless water heater. Keep in mind; these videos are for the Noritz brand heater. The descaling procedure is basically the same, no matter what brand you purchase. Always read the descaling instructions for your particular make/model.
How to descale your Noritz water heater.