About Scale Warning - Navien NR-20DU Manual

About scale warning

Scale warning
When the water heater needs to be cleaned, the
scale alarm is activated.
Current status and scale alarm code is displayed.
You can change the scale warning intervals if
desired.
Deactivating the scale alarm
Press and hold the OK button for 2 seconds.
"RST" is displayed for 3 seconds.
For Cascade systems
The following is displayed in turn:
Current status, alarm code, and Cascade ID.
You can change the settings and control them.
For details, see the Operation manual.
Note