The double check has two large ball valves with handles and four test cocks with slots. Test cocks are tiny ball valves, and all ball valves will trap water when fully open or closed. This trapped water may freeze and crack the brass body. The way to avoid freeze breakage is to leave these valves at a 45 degree angle. Half open, half closed. Note the handle above as well as the slot the screwdriver is in. Both ball […]