If the “SNOW SENSOR OVERRIDE” button is pressed, the system will run for the set amount of time which was programmed in to the user defined “AFTER RUN” field. To cancel the “SNOW SENSOR OVERRIDE” you must turn the system “OFF”.
Page 4 of https://www.warmlyyours.com/en-US/publications/ZONEBRAKER-TOUCHSCREEN-MULTI-ZONE-SNOW-MELTING-CONTROLLER-MANUAL-A.pdf