Troubleshooting for abnormalities due to Scale Build-up
C1#
If the alarm code “C1#” is flashing on the display window, it means there is scale build-up in the heat exchanger. Damage to the water heater due to scale build-up is not covered by the water heater’s warranty. To prevent damage to the heat exchanger from scale build-up, the heat exchanger needs to be flushed to remove the scale build-up. To clear the alarm code “C1#”, the heat exchanger must be flushed.
To resolve this issue, you need to follow the troubleshooting steps below.
This procedure is only intended to be performed a qualified service professional or authorized Noritz service representative.
Any unauthorized performance of this procedure may not be covered by the Noritz America Limited Warranty.
If the alarm code “C1#*” is displayed and flashing on the display window, contact Noritz America (1-866-766-7489).
*Warning indication, # = 1-9
For further technical assistance call 866-766-7489 or use our Contractor Locator to find a local service representative.