Noritz tankless water heater codes
A tankless water heater shows its fault as a number or letter code on the unit display or on the wired remote controller, and some models keep a short history of past codes. Write the code down exactly as shown before you reset the unit, and check the rating plate for the model number, because the same number can mean different things between series.
All 24 codes
06Recirculation flow too low (NRCR) (pro repair)10Combustion warning (can lead to code 90) (pro repair)11Ignition failure (pro repair)12Flame loss (pro repair)14Heat exchanger overheat (thermal fuse) (pro repair)16Outlet water temperature too high (pro repair)20High limit switch tripped (pro repair)29Condensate drain problem (pro repair)37Storage tank thermistor fault (Hybrid Hot mode) (pro repair)45Internal water leak (NRCP and CB models) (pro repair)50Continuous flow leak warning (pro repair)64No flow detected while circulator runs (Hybrid Hot mode) (pro repair)67AGM abnormality (pro repair)71Gas valve drive circuit fault (pro repair)73Circuit board setting error (pro repair)74Bluetooth communication problem (DIY)F76Multisystem communication error (DIY)760Remote controller transmission abnormality (DIY)79Pump control circuit malfunction (pro repair)90Airflow or combustion abnormality (pro repair)91Incorrect gas type (pro repair)92Neutralizer nearing end of life (first warning) (DIY)93Neutralizer at end of life (DIY)94Exhaust temperature too high (pro repair)
About Noritz codes
Noritz makes gas tankless water heaters that show a numeric error code on the display or the remote. Its help center documents each code, and the steps differ between residential and Pro Series premix models. Check the model label on your unit before using any chart.