Frozen Boiler Condensate Pipes: Finding The Freeze And Fixing The Problem

As your boiler converts fuel to energy, a steady drip of acidic water is created as a byproduct. This water is then transported through a condensate pipe to a drain located somewhere inside or around your house. In the winter months when temperatures plummet, any portion of your condensate pipe that is exposed to the weather can freeze up, forcing the water to back up into the system and eventually seizing your boiler. It's best to have this problem diagnosed and fixed by a professional, but if you're stuck in an emergency situation, read on to learn how you can do it yourself.

How Do You Know That Your Condensate Pipe Is Frozen?

Not all boilers have condensate pipes, but most modern, energy efficient units do. To identify whether or not your boiler is equipped with a condensate pipe, bend down and look underneath your unit. You should see a bunch of metal pipes that transport heat around your house, and a single plastic pipe -- this is the condensate pipe. If you find this plastic pipe, you'll likely find an exit pipe and a drain somewhere around the perimeter of your home. In most cases, this exit pipe will be the section that is frozen.

If you don't find an exit pipe and drain, your boiler condensate pipe drains into your plumbing system. In this case, you can still try to locate the frozen section by following the pipe to see where it may be exposed to extremely cold temperatures. For example, your pipe may run through your garage or your basement, both of which can be much colder than the inside of your home. 

Defrosting Your Condensate Pipe

Now that you've located the section of your pipe that is most apt to be frozen, you can attempt to defrost it with one of the below methods.

  • Hot Water - If you've identified that the frozen section of your condensate pipe lies outside your home above a drain, you can try to defrost it with hot water. Fill a watering can or large container up with hot water (not boiling), and pour is slowly and gently directly over the pipe. Most of the water should flow directly down the drain, but as a precaution, spread some salt around the area to prevent dangerous slippery spots.
  • Heating Pad Or Hot Towel - Another method of defrosting a frozen condensate pipe is to wrap the frozen section of pipe with a large heating pad or a towel that has been soaked in hot water. If using the towel method, switch the towels for new ones often as they begin to cool off.
  • Blow Dryer - If you have a hair blow dryer, you can try aiming it at the section of frozen pipe, sweeping it back and forth to evenly distribute the heat.
  • Space Or Salamander Heater - If the above methods fail, and your section of frozen condensate pipe lies in an enclosed area such as in your garage or basement, you can try warming up the area with a space or salamander heater. Put the heater inside the enclosed area, and set it to its lowest setting. Be sure to stay with the heater while it's in use to prevent the risk of fire.

Dealing With Recurring Problems

It's not uncommon to have a day or two a year when it's so cold outside that your boiler condensate pipe freezes up, but if you're dealing with the issue on a regular basis, it may be time to contact a professional boiler repair service for advice. Some common measures taken by professionals to prevent recurrent frozen condensate pipe problems include increasing the diameter of the pipe, weatherproofing the pipe, installing a heat cable along the pipe, or rerouting the pipe to drain into your plumbing system.  

If you happen to be reading this article before winter hits, you can avoid all of the hassle of dealing with a frozen condensate pipe by having your boiler system inspected by a professional. They can identify whether or not your condensate is at risk of freeze-ups, and offer some proactive advice on preventing an emergency situation.