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How To Fix A Frozen Boiler Condensate Pipe

It goes without saying that a frozen boiler condensate pipe is one of the things every homeowner, landlord, and tenant dreads. There’s no worse feeling than waking up in the morning and realising that your boiler has stopped working because of the cold weather. That feeling just gets worse when you notice that the cause of the breakdown is because of a frozen pipe. 

This guide will explain how to fix a frozen boiler condensate pipe and the things you can look for to pinpoint a smaller problem before it turns into a much bigger one. 

Your condensate pipe.

Condensing technology in boilers has been a requirement since 2005 in a bid to increase the energy efficiency of these home appliances. It means that the heat can be recycled and used again to heat the water. This is called the condensing process. 

What is a condensate pipe? It’s the pipe in which water is drained from and is disposed of with your usual waste water. As you can imagine, this pipe is essential. If it freezes internally, this can cause a lot of problems and should be fixed as soon as possible. 

Identifying your condensing pipe should be easy as it’s the only plastic pipe that is connected to your boiler. It should be a short length of pipe situated externally, which directly connects to your drainage system. It will also be angled to ensure waste water doesn’t flow back into the system.

Is my boiler condensate pipe frozen?

Is the external temperature below freezing? Has your boiler been working fine one day, then the next, you have no heating or hot water? Can you hear a strange sound coming from your boiler? If so, then this is an indicator that your pipe may be frozen. Your boiler may also be able to detect a frozen pipe and as a precaution, will prevent it from operating entirely. 

Here’s how to fix your frozen boiler condensate pipe. 

The first, most important thing to do is to locate the frozen pipe. It’s important that you don’t take drastic measures to move or remove the pipe entirely - a Gas Safe Registered engineer should be the only person to complete any physical pipe work. However there are things you can do to help fix the frozen pipe without the need for a registered professional to come to your home.

Warm up some water.

By using a kettle or a microwave, heat up a little water. The water shouldn’t be boiling, as this can cause further damage to your boiler pipe. The water should be at a warm enough temperature to thaw the frozen pipe a little, but not too hot ruin it. 

Pour the water over the pipe.

The frozen part of the pipe should be covered with the warm water. If you know where your pipe is frozen, you can target this area first. If not, you can start with the main outlet. This will help to unfreeze the pipe in different areas. 

Not fixed?

Sometimes, your pipes may be so frozen that a little hot water doesn’t quite do the trick. Another thing to try is to hold a hot object onto your boiler condensate pipe for longer, such as a hot water bottle, allowing the heat to be continuously applied. A trickling sound will indicate that the running water has been unfrozen.

Reset your boiler.

When you’re confident your frozen pipe is fixed, you can then try and reset your boiler. If it boots up as it should, you should be able to use your boiler as normal. If you’re still running into problems, or your boiler still isn’t working as it should be, there may be further problems. Contact your boiler manufacturer for assistance if this is the case.

How to prevent further frozen boiler condensate pipes.

If you’ve suffered because of frozen boiler pipes, then you need to take the necessary precautions to make sure it doesn’t happen again. There are two main things you can do: 

Insulate your condensate pipe.

By insulating your condensate pipe, you can prevent any future frozen pipes when the temperatures plummet. You can use waterproof insulation to ensure that your pipe will not get wet and freeze once more. 

Talk to a registered engineer. 

An engineer may be able to move the location of your condensate pipe so it’s inside a property. This means that it won’t freeze as the temperature is unlikely to drop below freezing here. Alternatively, they may be able to reroute the pipe or alter the angle of it to help improve water flow. 

Need help with a frozen boiler condensate pipe? Talk to us.

Having a boiler breakdown is enough to put anyone into panic mode. A condensing boiler frozen pipe is something that can be easily fixed or prevented with the right knowledge. Follow our simple steps to fixing the issue, or, if you’re finding your boiler is still running into problems, you can use our live chat to get advice from one of our qualified engineers.


We’re experts in boiler installation. If your current boiler is on its last legs, we’d recommend finding a brand new one to replace it with; it can be much cheaper than constantly replacing parts. Take a look at our Find A Boiler tool to find the perfect boiler for you and your home.

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