Noritz Tankless Water Heater Troubleshooting Error Codes 14 and 90

Familiarizing yourself with common error codes and Noritz tankless water heater troubleshooting solutions can be handy. Not all errors require a professional solution. Sometimes, you can deal with the issue as long as you know what you are dealing with.

Error codes typically represent technical issues in Noritz units. Each error code has its meaning and significance. If you are familiar with each code, you should deal with the issue efficiently, whether fixing it yourself or asking for professional assistance.

Noritz Tankless Water Heater Troubleshooting

Tankless Water Heater Error Codes

The tankless water heater unit is typically connected to a remote control with a display screen. You will see two-digit numbers on the screen when there is an issue, such as error codes 12, 90, 14, or 11. Each number has its meaning, referring to the issue and the core reason. For instance, error code 11 shows an issue with the ignition failure.

Read also: What Causes Noritz Error Code 90

You will get a Noritz tankless water heater manual when you buy the unit. Some of the error codes can be found there. But you can always check online if you can’t find them in your manual. Contacting their customer support is another alternative.

In short, you only need to check your remote control’s display screen and see the number. You can consult your manual, check online, or contact customer support.

Troubleshooting Types

Although Noritz units are designed to last, you can’t help it when you encounter minor issues during the operation. For instance, when you discover that your heater won’t ignite when water runs, you can always check whether the water IS running.

Read also: Rinnai Tankless Water Heater Code 11

You can also check for the water drain line filter, the crossed pipes, or the reversed plumbing. Or, when you notice that your heater tries to ignite but it doesn’t work, you can try resetting the unit again. The culprit may lie in the gas supply line and the air.

In some cases, homeowners find issues with the water temperature. You can try:

  • Checking the gas pressures. See whether it is cut off (by the gas meter or not)
  • Checking the water and gas valves. Are they fully open or not?
  • Checking the power button. Have you turned it on?
  • Checking the water drain valve filter, whether it is clogged or not
  • Checking whether the hot water fixture is open sufficiently

Noritz Error Code 14

One of the most common problems is error code 14, thermal fuse failure. The best solution is to replace the thermal fuse. You may want to check whether the unit doesn’t suffer from airflow or debris on the ignition plug restriction.

The gas should burn properly, too. The water quality should be good because poor water will affect the unit’s function in heat exchange. It may also lead to scale buildup, except if you flush on time.

Noritz Error Code 90 Fix

Error code 90 is about the gas combustion issue. The error code can be 90 or 99, but they are the same. You want to check that the color of the flame is light blue. Yellow tips are still allowed. Check the flue vent; see if there is any blockage or such thing alike.

After all, ventilation is crucial for gas heaters, especially for airflow. Ventilation is also crucial to eliminate carbon monoxide poisoning and to reduce risks. If you aren’t familiar with the unit, the best solution is to call a licensed contractor. They know what to do with the heater and how to perform proper checking.


Your manual would be your new best friend when caring for your water heater. Check it for minor Noritz tankless water heater troubleshooting issues, but if you can’t find the solution, ask for help from a licensed professional.

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