<!-- from fixya rte -->Error code 43 on 8.4 noritz - Noritz 8.4 Gallon Residential Direct Vent Tankless Water Heater - N

Remove the bird's nest in the flue.

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.

How To Resolve The Seven Most Common Noritz Tankless ...

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Nov 16, 2015 - This error code involves a breakdown in communication between two tankless water heaters using the Quick Connect Cord. It can occur when more ...

Troubleshooting Noritz Tankless Water Heaters and Error Codes

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Error code 90 and 99 ... Action: Check for the obstructed venting, improper gas burning (flame shape and color change). Ensure the water heater gets the ...

Error Codes for a Noritz Water Heater - Waterheatertimer.org

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I searched for that error number 903 using https://www.google.com and saw several fraudulent sites, so beware.

There is a similar error number 90 mentioned several places, but that error requires a technician to repair it as it may be dangerous to do it yourself.

Noritz in the United States has a search feature to find a technician if you need one.

https://www.noritz.com/home-owners/find-a-servicer/

Here is a link to all the Noritz error codes. There is NO Code 67. https://inspectapedia.com/heat/Noritz-NCC199-Error-Codes.pdf

https://support.noritz.com/download.php?file=Literature%20Page/Owners%20Guide/NRCP%20OG.pdf&field=OwnersGuide


https://support.noritz.com/download.php?file=Literature%20Page/Owners%20Guide/NRCP%20OG.pdf&field=OwnersGuide


Phone number to contact Moritz is on last page of manual.

The Noritz Manual shows fixed for the following error codes:
11
21
90
99
For all other codes this is the recommendation:
Contact our sales agent if:
• Any other error code appears.

http://www.noritz.com/u/pages_from_field_manual_2010_12_09_pdf__adobe_acrobat_professional.pdf



The Noritz field manual says that error code 66 is Bypass Water Control Valve failure. Call support at 866-766-7489 with your model #, serial # (both on the unit face plate), date of purchase, to see if the valve can be replaced under warranty.

There is no error 43 on a NR71. There is a 73 error code which is caused by disconnecting jumper cables while the power is on.

a 16 error code is typically caused by scale formation. I'd recommend performing a descale on the heater.

I called Noritz error code 16 is a overheat problem. Noritz say's to flush your coil with vinegar or CLR.
Use a small pump to recirculate the CLR or vinegar through the system for 45 minutes and flush with fresh water. This worked for me.