Does your high efficiency furnace or boiler stop working during extreme cold temperatures?

Condensing furnaces and boilers (typically greater than 90% efficient), produce water during the heating cycle. This slightly acidic water leaves the system via a drain pipe (condensate line). During extreme cold temperatures, this water can freeze inside of the drain pipes. When this occurs, it can cause minor flooding and/or cause your furnace to shut off entirely. This issue is more common when the appliance has been installed in an attic or when the condensate drain line has been installed in an exterior wall. If you suspect that this could be the reason your heater has stopped working you should check for any ice buildup in or around your heater’s vents and drain pipes.

Thawing Frozen Pipes

An electric hair dryer can be a useful tool to thaw frozen pipes. Simply direct the hot air towards the frozen pipe. If the frozen pipe is made of plastic, such as PVC, you should avoid overheating the pipe by taking short breaks that allow the plastic pipe to cool. An electric hair dryer may also be useful when pipes are frozen inside a wall. Of course, this method requires patience and short breaks to keep from overheating the wall surface and electric hair dryer are necessary.

Hot water can also be used to thaw frozen pipes when the pipes are accessible. In areas where water damage is not a concern, you can pour the hot water directly over the frozen pipe. In areas where water could cause damage, such as in an attic, you can dip a sponge or rag into the hot water and repeatedly wipe the outside surface of the pipe.