Originally Posted by avanti
Do you happen to remember whether the damaged valve was left open or closed? I always leave mine open, and have wondered whether it matters or not.
It broke on the shower fixture side of the valves, so only leaked (behind the wall) when the shower valves were opened. Didn't find the leak until we were at a campground & taking a shower, of course.
My guess is that leftover water ran back down the shower hose into the valve after blowing it clear, then froze and cracked the back side of the fixture on the low pressure side of the valves.