How to thaw a condensate pipe

Has your boiler stopped working overnight?

If it happens after a freezing night, don’t panic—your condensate pipe may be frozen.

And if that’s the case, it might be time to put the kettle on…

From locating the blockage to restarting your boiler, we grilled our Home Experts on how to sort out the problem and get your home warm again in no time.

What is a condensate pipe?

A condensate pipe carries condensation from your boiler to your outside drain.

It’s usually a white or grey plastic pipe that travels from your boiler through the wall directly outside where your boiler is located.

During cold weather, the condensation in this pipe may freeze and cause a blockage causing the condensation to back up into the boiler and cause it to shut down.

Even if you take the utmost care of your boiler, it will struggle to function if its condensate pipe freezes. 

In our blog below, one of our Home Experts, explains exactly how to thaw a condensate pipe safely.

Here is a complete procedure of how to thaw a condensate pipe if frozen –

Step 1: Confirm the condensate pipe is frozen

Depending on the make and model of your boiler, a frozen condensate pipe may be indicated by a ‘fault code’ or warning light on the boiler’s display.

Gurgling or bubbling sounds coming from the boiler or the condensate pipe is another sign that the condensate pipe has frozen.

Here are some most common boiler error codes that will help you to identify a frozen condensate pipe

If you do not see your boiler here you can search for the error code of your particular boiler, you can easily get this in the user manual provided.

Step 2: Locate the blockage

At its exposed point, the pipe might be frozen.

This may be the open end of the pipe, or at a bend or elbow.

Running your hands over the pipe until you find a section that feels colder than the rest should help you identify the blockage quickly.

Most condensate pipes freeze near the ground, so it’s simply a case of slowly pouring hot water over the pipe.

Step 3: Use hot water to thaw the pipe

First, boil some water. If you’re using a kettle, cool it for at least 15 minutes once it’s boiled.

Do not use boiling water as this can crack or damage the pipe.

Using a jug or watering can pour hot water along the length of the pipe, repeating the process until the pipe has thawed.

Be careful where you pour the water—it may freeze and become a slip hazard.

Alternatively, you can use a hot water bottle or a heat pack to slowly defrost the condensate pipe.

Step 4: Restart your boiler

Once the frozen section has been melted and cleared, check your boiler manual for instructions on how to reset the boiler correctly. Your boiler should now restart.

Step 5: Not fixed? Keep trying

It may take several attempts before your boiler restarts, but if it doesn’t, you may need to call out a qualified boiler engineer.

Is the boiler still not working?

If you’ve followed our advice on how to thaw a condensate pipe but your boiler still isn’t working, try diagnosing your central heating problems.

Alternatively, you may need to call out a qualified boiler engineer.

PlusHeat’s nationwide network of gas-safe engineers is here to help.

Get a quality boiler cover to have peace of mind regarding your boiler.

Simply get in touch, safe in the knowledge you can count on us to keep you feeling toasty this winter.

Also Read –

• How do you stop your pipes from freezing this winter? 
• Frozen Boiler Blocked Pipe – A Fix