Error Codes for a Noritz Water Heater

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Many homeowners rely on a water heater to provide a steady supply of hot water for baths and showers. Noritz water heaters are widely used because they are tankless models are able to supply hot water on demand and at a greater volume. These heaters also feature a remote controller that displays error codes that allow homeowners to quickly troubleshoot issues with their heater. If you own a Nortiz water heater, learning these codes may save you even more time if a problem develops with your heater.


10, 59, 90, 99

The 10, 59, 90 and 99 error codes indicate that a Noritz heater has experienced a combustion abnormality. In most cases, it is the result of an obstruction in the heater's flue. Examine the flue to see if it is blocked by debris and clean if necessary.


When the 11 error code appears in your Nortiz heater's remote controller, an ignition failure has occurred. Check to see that the gas valve has been opened so gas can reach the heater. Make sure that the heater is set up for the type of gas that you have attached as well. In addition, the heater may fail to ignite if there is a problem with the igniter connection, so check to see that it is firmly attached. Examine the flame rod connection as well. If you are using liquid propane gas in your Noritz heater, check the tank to make sure that it is not empty.



The 16 error code indicates that your Noritz heater is experiencing an abnormally high output temperature. Test the outlet water temperature to make sure that it is not too hot. You heater may also operate at higher output temperatures if the outlet water is hard, so you may need to use a water softener to lower the temperature. In addition, poor water pressure may cause increased output temperatures so make sure that your pressure measures at least 25 lbs. per square inch (PSI). Finally, if you have a filter attached to your water supply, check to see if the strainer or pre-filter has become clogged and remove any obstructions.



When the 21 error code appears, there is a pressure switch abnormality with your Noritz heater. Examine the switch for any obvious defects. The fan motor may also cause this type of abnormality so check that it is in proper working order as well. In addition, a blocked flue may also cause issues with the pressure switch so examine it for any possible obstructions.


A 29 error code indicates that there is an abnormality with the neutralizer water level electrode in your Noritz heater. Examine both the neutralizer and drain pipe for possible obstructions, and verify that the water level electrode has been properly connected to the heater.



When your Noritz heater's remote controller displays the 410 error code, the heater is experiencing a multi-system flow imbalance error. Examine the heater's flow to ensure that it is not blocked, and check its filter and sensor for signs of damage or debris that might prevent them from operating properly.


A 56 error code appears when there is an abnormality with your Noritz heater's CCP valve. This code may appear if the heater's flow is blocked, so examine it for possible obstructions. The CCP valve itself may be the issue, so use the system controller to check that the valve is operating properly.



The 61 error code indicates that there is a problem with your Noritz heater's fan motor. Check to see that the fan rotates normally.


The 73 error code indicates an improper circuit board setting. Check the circuit board for any signs of damage or improper connections. If the circuit board's wiring has been adjusted while the heater is in operation, unplug the unit and replug it in to reset the connections.


92, 93

Error codes 92 and 93 alert you when your Nortiz heater's neutralizer's life cycle is about to end or has ended. Immediately replace the neutralizer according to the replacement neutralizer's instructions to clear the error.



Jennifer Blair

Based in New York City, Jennifer Blair has been covering all things home and garden since 2001. Her writing has appeared on, World Lifestyle, and House Logic. Blair holds a Bachelor of Arts in Writing Seminars from the Johns Hopkins University in Baltimore, Maryland.