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If it’s freezing cold outside and your boiler stops working, there may be a problem with your condensate pipe. Follow the steps below to thaw a frozen condensate pipe, or watch the short video below which explains the simple steps to take.

1 To thaw frozen boiler pipes, hold a hot water bottle or heat wrap around the pipe
2 Alternatively, pour hot, NOT boiling, water over the frozen end of the pipe
3 If the boiler fires up, it’s fixed. If it doesn’t, pour hot water on the pipe again. If your pipes are still frozen, call your supplier.

Has your boiler condensate pipe frozen?

When gas is burnt, as well as producing heat and light, it also produces carbon dioxide and water vapor – this is the steamy ‘plume’ that can be seen from a boiler flue on cold days. As this water vapor is ejected from the flue, water droplets form on the side of the flue and runs back into the boiler. Modern boilers are designed to catch this ‘condensate’ and drain it away through a ‘condensate pipe’.

Condensate must be disposed of in the right way (into a suitable drain) because it contains contaminants that make it slightly acidic and would cause damage if left to drain onto surfaces or soil. 

All new boiler installations are condensate, so it’s likely you’ll have one of these if you live in a new home or a home where the boiler has been replaced in recent years. Your boiler condensate pipe can sometimes be found protruding from the walls of your property and leading into a drain and it’ll usually be made of plastic.

In cold weather, the water that passes through these pipes can become frozen, blocking the pipe and allowing condensate to build up in the boiler. To prevent itself from flooding, the boiler will switch itself off. It’s important to get this fixed as quickly as possible to avoid your boiler switching itself off and leaving your home without heat.

Do you have a frozen boiler condensate drain?

So how do you know if you have a frozen boiler condensate drain connected to your boiler? One of the main signs of this problem will be that your boiler has turned itself off and left you without any heating or hot water. But before getting to that point, you may also notice a strange gurgling sound coming from your boiler and near the pipe outside your home.

Now would be a good time to try and locate your condensate pipe, helping you stay a step ahead if you do have any problems in the future. If you experience particularly cold and frosty weather, you can then carry out a quick check on the pipe to make sure everything seems to be in order – if you see water coming out, the pipe should be working.

If you do think you’ve diagnosed the problem of a frozen condensate drain, here are a few steps you could try to help clear the problem:

  • Apply a hot water bottle or a warm heated pad to the pipe in order to warm it up and begin thawing the water.
  • Fill a watering can or a jug with warm (not boiling) water and pour it over the pipe.

By doing this, you should start to notice the pipe clearing out any blocked water and functioning again. If you’re unsure whether you’ve cleared the blockage and are still experiencing problems with your boiler, contact a professional Gas Safe Registered engineer to take a look.

Any work directly on your boiler should always be carried out by a Gas Safe Registered engineer to ensure that it’s done safely and to a high standard. Ensuring your boiler is serviced annually will help to avoid these and many other problems, such as carbon monoxide leaks from your boiler.