Troubleshooting Your Noritz Water Heater

Jan 11, 2021

There is so much technology around us that we normally don’t give it a second thought – as long as it works! 

But there are no perfect human inventions. So, even with products made to high standards, there are bound to be a few glitches from time to time.  

tankless water heater on wall

We install only high-quality Noritz tankless water heaters. Noritz is a leading North American manufacturer of tankless water heaters that impress with their energy efficiency and overall performance. Even so, any tankless water heater can have a hiccup – and a little troubleshooting can get everything up and running smoothly once again.

5 Common Noritz Tankless Water Heater Error Codes


Error Code 11

Meaning: Ignition failure – no water will be heated.

Possible cause: Insufficient gas supply, problems with airflow, or debris on the ignition plug.

How to fix: Make sure your gas is on. If it is, call Arnett’s Water Systems to check gas pressures and test the spark.  


Error Code 16

Meaning: Water temperature spikes to an abnormally high value.

Possible cause: Considerable scale buildup in your water heater.

How to fix: Annual maintenance, using a descaling procedure or water softener. Do it yourself or call us and we’ll do it for you.


Error Code 29

Meaning: Issue with condensate drainage.

Possible cause: Line is blocked or proper drain piping not used.

How to fix: Clean out the container and drain line of any debris or blockages.  


Error Code 73

Meaning: Improper circuit-board settings.

Possible cause: Jumper connection or dip switch is changed while power is supplied to the heater. 

How to fix: Unplug the heater for 30 seconds and then plug it back in. If this does not resolve the issue, call Arnett’s Water Systems for help.


Error Code 90

Meaning: Combustion abnormality.

Possible cause: Improper mixture of air and fuel.

How to fix: This issue requires the skills of a licensed plumbing and/or heating contractor to check gas pressures, venting length and dip switches for the cause of the issue. When you see this code, contact Arnett’s Water Systems right away!


Why It’s Important to Check Error Codes


Noritz makes tankless water heaters to the highest standards, but the chance for an error code to show isn’t null. The codes can tell about the problems that may go unnoticed otherwise. They can help you identify the problem sooner, saving you the costs of possible repairs later on. Even so, the error codes aren’t always clear for the owner.

Bear in mind that Noritz tankless water heaters come with sophisticated features and elements that are connected, with the electronic board controlling the elements. You need both the skills and the knowledge to solve any troubleshooting. 


How to Reset Your Noritz Tankless Water Heater


If nothing else works, you can try resetting the water heater.  

(If your tankless water heater is shutting off by itself, this is NOT normal.) You should:

  1. Check for power.
  2. Unplug the unit from the wall and wait for two minutes before plugging it back in. Please note that turning the water heater off with the remote control doesn’t do anything. This leads to a common mistake of thinking that the remote control or the thermostat is defective. The units are all factory set at 120 degrees and will operate at that temperature – even if you were to cut the remote.

Note from Erik Arnett: “In twenty years of servicing Noritz, I’ve never had a defective remote. If your tankless water heater is turning itself off, you have underlying problems – the water heater is turning your remote off, not the other way around.”