How to unfreeze a frozen condensate pipe


Winter is approaching and, as usual, newspapers are predicting it will be the coldest one ever. That remains to be seen, but if we do get a cold snap, you won’t want to be without a working boiler. Getting a regular boiler service can help you avoid problems when winter comes, but there’s also a common issue that can stop your boiler from working. It involves your boiler’s condensate pipe and luckily, it’s quite easy to fix.

What is a condensate pipe?

A condensate pipe runs from your boiler to the outside of your property. It’s necessary, because when your boiler burns gases to produce heat, it also produces condensate. This needs to be released and this is done through the condensate pipe. They exist because modern boilers reuse hot waste gases to produce even more heat.

This makes them much more energy efficient than old boilers, but means they also produce moisture which needs to be carried outside by a pipe. If the pipe becomes blocked then the boiler cannot safely get rid of the condensate and has to shut down.

How to find your condensate pipe?

Your condensate pipe will be outside your property and should be close to wherever your boiler is located. It will likely be a thin grey or white coloured pipe that will be running into a drain or drainpipe. It may be insulated, in which case you’ll need to remove the covering before attempting to defrost the pipe. They are often placed near ground level but may sometimes be higher up, in which case it might be better to leave the job to a professional boiler engineer or plumber.

Unfreezing your condensate pipe

Once you have found the pipe, you’ll need to warm it up to melt the blockage inside. You can do this by pouring hot, but not boiling, water over the length of the pipe. Boiling the kettle and letting it cool down a bit should do the job. You could also get a little bit creative and use a hot water bottle or a heat wrap. These methods can be effective but also might be less straightforward to use, depending on the position of the pipe.

Why do condensate pipes freeze?

Once temperatures drop to a certain point, the liquid being released is frozen and blocks the pipe. Pretty straightforward! However, the reason this can happen in the first place is that in the UK we don’t regularly experience winters cold enough to freeze external pipes. That can mean that condensate pipes aren’t always insulated properly, leaving them exposed to the elements.

How to stop condensate pipes freezing

Check whether your pipe is properly insulated, it should be covered in a foam-like material that will prevent it from getting too cold. If you’re a bit handy, you might feel like attempting the job yourself, but if not, it’s quite an easy task for a qualified professional to look after. It means that if the big freeze comes, you hopefully won’t be stuck outside in your dressing gown splashing a kettle of warm water over the pipe and possibly your slippers.

If your boiler’s not working, it might not always be the condensate pipe’s fault, especially if the weather’s not that cold. Here’s a few more fast fixes for your broken boiler that might help get it working again.