Hello. I had a frozen pipe in my wall that went from my basement, through a laundry room, and upstairs to a washroom. I think the pipe got frozen when a back door was left open a crack and cold air got into a wall vent. I didn't want to open the wall to make sure the pipe was not damaged, so first we shut the water off then we just heated the inside of the wall slowly by pointing a micro-furnace heater at the wall vent and let the pipe thaw out that way. We didn't want to do it too quickly because the pipe may have burst. After about 6 hours we turned the water back on and everything seemed OK. Thanks for the advice! Steven P.