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Frozen Condensate Pipe & How To Thaw It DIY Tips

Frozen condensate pipe – how it is caused and how to fix it?

During the Winter, many things are at risk of getting frozen, mainly due to the freezing temperatures that occur at that point of the year. Your condensate pipe is another part of your household that can often freeze over with the cold weather, which can cause a lot of issues to your boiler and central heating system.

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frozen condensate pipe

When your condensate pipe freezes, this can cause a lot of problems for your boiler, to the point where an error code is displayed and your boiler doesn’t work efficiently. This will mean that you are paying your heating bills for an ineffective heating system, costing you quite a bit.

However, don’t worry too much, your boiler isn’t completely broken or in need of replacement, you just need to safely thaw your condensate pipe and your boiler should be up and running again in no time.

To thaw a frozen condensate pipe, you should either:

  • Pour hot water (not boiling) over your condensate pipe to melt the ice.
  • Place a hot water bottle on the pipe to slowly melt the ice blockage.

What is a condensate pipe?

condensate pipe

A condensate pipe is a component of your boiler that transfers condensed waste water out of your home via a waste pipe. This water has acidic traits meaning it isn’t exactly something you want to be kept in your heating system. Your condensate pipe can usually be easily identified as it is a white plastic pipe external to your home.

This is why it is important that your condensate pipe remains clear and any blockages should be removed as soon as they can.

Boiler condensate pipe location

boiler parts

Before even knowing if your condensate pipe is frozen, you will need to locate it first to be able to inspect it. As we have said previously, the condensate pipe is an external component of your boiler and is usually located outside of your home.

It should be the only plastic pipe connected to your boiler and is usually either white or grey. A condensate pipe should be connected to your boiler at one end and to some form of external drain pipe at the other, so the waste water can be safely drained from your system.

How to know if your condensate pipe has frozen

There are some signs that you can look out for if you suspect you have a frozen pipe, which will occur under cold temperatures, causing the freeze. One of the most prominent indications that you have a frozen boiler condensate pipe is you may hear a gurgling noise coming from your boiler. These gurgling noises will usually mean that your boiler has shut down as a precaution, meaning it is important to listen out for these noises.

noisy boiler

In fact, this is a feature in almost all condensing boilers, so if you notice that your boiler has stopped working and you have a complete lack of hot water, this may be one of the causes.

When condensate pipes do get a frozen section, a fault code will usually appear on the boiler’s display to let you know that something is wrong. Not all fault codes mean the same thing, so it is also important that you look out for certain ones that suggest frozen condensate pipes.

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Frozen condensate pipe error codes

There are many different boiler brands out there which have a range of fault codes signalling that there is an issue with your boiler. Each manufacturer will have different fault codes for a condensate pipe freezing, so we will let you know the most common ones to look out for from some of the top boiler brands.

Some of the codes to look for are:

How to thaw a frozen boiler condensate pipe

Now that you’ve located your condensate pipe and can see that it has frozen over, it’s time for you to do something about it. There are a number of locations where freezing is most likely and these are the joints/elbow of the pipe and the exit of it, as most of the water will collect here at any given time.

pouring warm water on condensate pipe

It should be quite clear whereabouts of the pipe is frozen, so if it isn’t one of these spots, you will likely be able to tell. Regardless of where the freezing is, the same methods are applied to thaw a frozen condensate pipe.

Make sure to follow instructions carefully so as to not damage your boiler or cause any harm to yourself and potentially others.

Pour warm water over your condensate pipe

  • Firstly, heat some water up in the kettle so that it can be poured over the condensate pipework. However, this shouldn’t be boiling water as you don’t want to damage the pipe.
  • Carefully pour the water over the frozen pipe to melt the ice away. This can be directly from the kettle if the water isn’t boiling or from a jug if you allowed the water to cool first.
  • Once it is unfrozen, restart your boiler.

Use a hot water bottle to unfreeze the pipe

  • Pour warm water into a water bottle.
  • Place the bottle next to the frozen spot of your condensate pipe.
  • Restart the boiler once it is unfrozen.

How to prevent frozen condensate pipes in the future

Now that you have managed to unfreeze your condensate pipe, there are a few ways to prevent the condensate pipe from freezing moving forward. Taking these preventive measures can end up saving you a lot of trouble, especially during low temperatures.

Insulate your pipes

During the Winter, it is important to protect and keep your condensate pipe warm to reduce the chances of it freezing again. One way of protection is to add a layer of foam pipe insulation around your condensate pipe, which will not only keep it warm but will also prevent the condensate pipe from freezing.


Move the condensate pipe

If you live in an area that can get quite cold and have to deal with condensate pipes freezing a lot, then you might want to consider moving your pipe. Moving it so that it is in a place with a higher temperature such as making it internal to your home, will be a big step towards no longer having frozen pipes.

Change the pipe’s fall angle

Changing the pipe’s fall angle so that water flow increases is another method to stop freezing. With an increased water flow, it should much faster through the pipe meaning less water will get collected in the joints of the pipe and, therefore, reduces the chances of freezing.

To do this, however, you will likely need a heating engineer to change the angle, as this isn’t something that is easily done.

thermostat temperature

Increase heating system temperature

Another option that you could consider is turning up the temperature of your boiler and your system, as the higher temperature of the water should make it harder for the water to freeze. However, this will also likely increase heating bills, so this should really be a last resort.

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