How to Fix a Frozen Condensate Pipe

During winter, we need our boilers more than ever. While the temperature may be freezing outside, at home we can remain toasty and warm thanks to the heat our boiler provides. However, winter is the time when our boilers are most likely to break down, which is unfortunate as it’s when we need them the most!

One of the most common reasons for boilers to stop working during winter is due to frozen pipes. When the weather outside drops to freezing or below, the water in the pipes can freeze, blocking the flow of water around your system - and the condensate pipe can regularly fall victim to this.

What in a condensate pipe?

The condensate pipe is part of every combi boiler. It allows for the recycling of heat within your boiler, meaning it helps save energy and prevent waste. When the heat from the flue gases is caught to be recycled back into the system, there is a dramatic drop in temperature which causes condensation. The job of the condensate pipe is to drain this away.

Sometimes the condensate pipe can be fitted internally, which is advisable and makes freezing less likely. However, this often is not possible due to various factors including the location of the boiler and the flue. When the condensate pipe is fitted externally, it’s at high risk of freezing because of all the water it deals with and because it is made from plastic, rather than metal. If your condensate pipe runs through your garage or a similar outbuilding, it will also be at risk of freezing.

If your boiler appears to be working but the radiators or hot water aren’t being heated, the issue could be a frozen condensate pipe. Some boilers show fault codes which can indicate a blockage in the pipe, but otherwise if it’s freezing outside and your boiler isn’t playing ball then a frozen condensate pipe is probably a safe bet.

How to fix a frozen condensate pipe

Firstly, you need to locate your pipe, which is usually quite easy to do as it will be the only plastic one connected to your drainage system. It should be between 22m and 32mm in diameter and it’s likely to be positioned at a steep angle, which helps prevent other water travelling up it. Your condensate pipe will usually be positioned fairly low, at a similar height to your ground floor windows.

Follow these simple steps to defrost your condensate pipe:

  • Warm some water but don’t boil it. Boiling water can damage the plastic pipe, and is also a safety risk should you slip or spill it.
  • Pour the water over the length of the pipe, including any flatter sections or curves.
  • If the pipe starts to defrost, you may hear a trickling noise as the water begins to flow again.
  • If the pipe is still frozen, put a hot water bottle on it as this can thaw it out further.
  • When the pipe seems to have thawed out, your boiler can be reset and should work as normal.

After this you can enjoy being in the warm inside once again, perhaps with a well deserved cup of tea or coffee as well!

Helping to prevent further freezes

Hopefully this is all you need to do to restore your heating and hot water. However, your condensate pipe is at risk of freezing repeatedly over the winter months and waking up in a cold property without any hot water is no fun for anyone.

To help prevent your pipe freezing again, you can insulate it yourself. This is simple to do, with some waterproof foam lagging tubes, which can be bought from your local DIY store. Simply wrap the foam tubes around your pipe carefully, ensuring it is fully covered. This will help provide some insulation to your condensate pipe and lower the risk of it freezing over again.

Need a boiler repair in Harlow? 

If you don’t feel confident trying to fix your frozen condensate pipe, or if your boiler is giving you other grief, you can call on us. The team at D A Gas, Heating & Plumbing are experienced in all aspects of gas boiler repair work, and have solved more pipe issues than we can count! We work in homes across Bishop's Stortford, Sawbridgeworth, Epping, Stansted, Great Dunmow, Hoddesdon and Ware - always providing the highest levels of service.

We’re Gas Safe registered, fully knowledgeable, and friendly and reliable to boot. You’ll see even more reasons to hire us when you take a look at our excellent customer reviews and look through our gallery of work carried out.  We’re also a Which? Trusted trader and proud members of the Checkatrade directory.

To find out more about what we do or how we can help, simply get in touch. You can call us on 07920 875189 or 01279 316304, email us at or fill out our short online contact form.