As a proud owner of a Noritz tankless water heater, you can enjoy endless hot water on
demand, energy savings, and a compact design that takes up less space than traditional tank
water heaters. However, like any other appliance, your tankless water heater may experience
occasional malfunctions or error codes that require troubleshooting and repair. Knowing what
these error codes mean and how to fix them can help you avoid costly repairs and extend the
life of your water heater. In this article, we'll cover the most common Noritz tankless water
heater error codes and their meanings.
Noritz Tankless Water Heater Error Codes:
1. Noritz Error Code 10 - This error code indicates a flame failure or flame loss in the
combustion chamber. Check the gas supply, igniter, and flame sensor for any issues, and clean
or replace them as necessary.
2. Noritz Error Code 11 - This error code indicates an ignition failure, which can be caused by a
malfunctioning igniter or gas valve. Check the igniter and gas valve and replace them as
necessary.
3. Noritz Error Code 12 - This error code indicates a flame loss during operation, which can be
caused by low gas pressure, insufficient combustion air, or a dirty or damaged flame sensor.
Check the gas supply, combustion air supply, and flame sensor, and clean or replace them as
necessary.
4. Noritz Error Code 14 - This error code indicates a thermal fuse failure, which can be caused
by a malfunctioning fuse or overheating in the heat exchanger. Check the fuse and heat
exchanger and replace them as necessary.
5. Noritz Error Code 16 - This error code indicates overheat protection, which can be caused
by low water flow, dirty or clogged filters, or a malfunctioning heat exchanger. Check the water
flow rate, filters, and heat exchanger, and clean or replace them as necessary.
6. Noritz Error Code 21 - This error code indicates a gas inlet temperature sensor failure.
Check the sensor and wiring connections and replace them as necessary.
7. Noritz Error Code 22 - This error code indicates an outlet temperature sensor failure. Check
the sensor and wiring connections and replace them as necessary.
8. Noritz Error Code 29 - This error code indicates heat exchanger overheat protection, which
can be caused by low water flow, dirty or clogged filters, or a malfunctioning heat exchanger.
Check the water flow rate, filters, and heat exchanger, and clean or replace them as necessary.
9. Noritz Error Code 31 - This error code indicates an inlet thermistor failure. Check the
thermistor and wiring connections and replace them as necessary.
10. Noritz Error Code 32 - This error code indicates an outlet thermistor failure. Check the
thermistor and wiring connections and replace them as necessary.
11. Noritz Error Code 33 - This error code indicates a heat exchanger thermistor failure. Check
the thermistor and wiring connections and replace them as necessary.
12. Noritz Error Code 51 - This error code indicates a fan motor failure. Check the motor and
wiring connections and replace them as necessary.
13. Noritz Error Code 52 - This error code indicates an exhaust blockage. Check the exhaust
venting and clean or remove any blockages.
14. Noritz Error Code 59 - This error code indicates overheat abnormality, which can be
caused by low water flow, dirty or clogged filters, or a malfunctioning heat exchanger. Check the
water flow rate, filters, and heat exchanger, and clean or replace them as necessary.
15. Noritz Error Code 90 - This error code indicates combustion abnormality, which can be
caused by a malfunctioning gas valve, improper gas pressure setting, insufficient combustion air
supply, or a dirty or damaged flame sensor. Check the gas supply, gas pressure, combustion air
supply, and flame sensor, and clean or replace them as necessary.
16. Noritz Error Code 92 - This error code indicates a neutralizer abnormality, which can be
caused by a clogged or damaged neutralizer or improper installation. Check the neutralizer and
installation, and clean or replace it as necessary.
17. Noritz Error Code 99 - This error code indicates a communication error between the control
board and other components. Check the wiring connections and replace any damaged
components as necessary.
18. Noritz Error Code 108 - This error code indicates a flow sensor failure. Check the flow
sensor and wiring connections and replace them as necessary.
19. Noritz Error Code 111 - This error code indicates a hot water outlet thermistor failure.
Check the thermistor and wiring connections and replace them as necessary.
20. Noritz Error Code 112 - This error code indicates a cold water inlet thermistor failure.
Check the thermistor and wiring connections and replace them as necessary.
Now that you know the Noritz tankless water heater error codes and their meanings, you can
troubleshoot your unit; however, we highly recommend you contact a water heater specialist for
assistance. Regular maintenance, such as descaling the heat exchanger, cleaning or replacing
filters, and inspecting components for wear and tear, can also help prevent error codes and
prolong the lifespan of your water heater.
The Water Heater Company is a small family-owned and operated business. We are Noritz
Authorized Service Providers so if you are in our service area and need assistance with your
tankless water heater, give us a call. We look forward to helping you with your water heater
repair and maintenance needs.
