During testing the number 1 shut off valve for Wilkins 975xl2 1 1/4 inch backflow device froze in closed position and handle shank broke off. Dis assembled backflow and valve and turned to open position ****this valve is still not functional and is frozen in open position. Will need to order tapped valve and return to install. Ace Pelizon Plumbing will shut water off to building and replace existing number 1 shut off valve on backflow device that failed during annual testing. Will restore water to system and verify function of device.