Rinnai 14 Error Code: Heat exchanger overheat

The heat exchanger overheated. The manual points to the overheat switch, scale build-up blockage and flushing the heat exchanger.

Is it safe to keep running? No. Turn it off and get it checked. Call a qualified professional to inspect and flush the heat exchanger. The manual says hard water must be treated to prevent scale build-up.

🛑 Stop and call a licensed pro if

• Call a qualified professional to inspect and flush the heat exchanger. The manual says hard water must be treated to prevent scale build-up.
• You smell gas. Leave the house, do not touch switches, and call your gas utility from outside.
• Codes for flame failure, overheating, venting or the control board that return after one reset.
• Water leaking from the heater, the relief valve discharging, or scorching around the burner area.
• A carbon monoxide alarm sounds. Get everyone outside and call 911 or the fire department.

Safe first steps for any Rinnai code

1. Write down the exact code shown on the controller or the number of status light flashes.
2. Turn the water heater power off and back on (or press the reset button the manual describes) once. If the code comes back, stop resetting.
3. Make sure the gas supply valve to the heater is open and other gas appliances in the home are working.
4. Make sure the cold water supply valve is fully open and hot water taps are not partly closed.
5. Look at the outside vent terminal for snow, ice, leaves or anything blocking it (look only).

Ryan Giles · Red Seal Certified Plumber · Ask a plumber · Ask an HVAC technician