Attempted to test 3 backflow preventers. Domestic water: 2 inch RP Make: watts Model: 909HWM1QT - inlet ball valve froze and split Fire sprinkler bypass? 1-1/2 inch RP Make: watts Model: 909M1QT - this backflow has an alarm on the inlet gate valve. Fire sprinkler 4 inch DC Make: Ames Model: 2000SS inlet and outlet valves are not holding for technician to replace #3 test port valve. That test port valve froze and split. Recommended to replace all 3 backflow due to freezing.