The Ice Sweeper turns on at 41 degrees and turns off at 42 degrees (Automatically).  It is a thermal sensing valve that is constantly in contact with the water and “intermittently” releases enough water to prevent surface ice, as the water temperature dictates. No more – no less! It will Keep your water hose from freezing up to 150' as well as keep water open in your Stock Tank to allow animals access during colder months!