Thawing a Frozen Water Pipe
When your pipes are frozen water will come out in a trickle, or not at all. If your pipe is frozen, but not yet burst be sure to open the faucet that is supplied by the pipe regardless of whether or not you know where it’s frozen. Follow the pipe from the faucet to where it runs through cold areas such as an exterior wall or an unheated crawl space. Look for frost or ice on the pipes. The pipe may be slightly fissured or even bulged.
If the pipe is exposed you can use a hair dryer to thaw it. Make sure to work from the faucet towards the frozen area. If the pipe is close to a wall you can place a cookie sheet behind the pipe to help radiate the heat to the back of the pipe. If you do not have a hair dryer you can also use a heat lamp. Be sure to leave the main water vale open when thawing a frozen pipe.
If the frozen pipe is behind a wall you can turn up the heat in the house and wait for the pipe to thaw, or you can tear out a section of the wall or ceiling to expose the pipe. Once it is exposed you can thaw using the above methods. You can also use an infrared lamp. This will allow you to heat sections of the wall where you believe the frozen pipe is without tearing out drywall. Infrared lamps pass though the air without heating the air and direct more energy to warming the wall and thawing the pipe. If at any time the pipe bursts before it is thawed immediately turn off the water main.