Has your boiler stopped working overnight? If it’s happened after a particularly cold night, don’t panic—your condensate pipe may just 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 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.
How to defrost or thaw a condensate pipe
Even if you take the utmost care of your boiler, it will struggle to function if its condensate pipe freezes. In our video below, one of our Home Experts, Chris, explains exactly how to thaw a condensate pipe safely.
Check out our handy step-by-step guide below, or you can always read the video transcript.
However, if you don’t feel confident when following this guide then you should contact an expert boiler engineer for help.
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 are another sign that the condensate pipe has frozen.
Step 2: Locate the blockage
The pipe is probably frozen at its most exposed point. 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 to the ground, so it’s simply a case of pouring the hot water over the pipe slowly.
Step 3: Use hot water to thaw the pipe
First, boil some water. If you’re using a kettle, make sure to cool the kettle 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.
Infographic: How to thaw a condensate pipe
On the go? Our handy infographic sums up how to thaw a frozen condensate pipe:
How to stop your condensate pipe from freezing
It’s easy to thaw your condensate pipe once it has frozen, but it’s better to prevent your pipes from freezing in the first place. We asked Home Expert Chris for tips on how to stop your condensate pipe freezing, and save you the hassle of waking up to no hot water.
Wrap it in some old towels
If your condensate pipe isn’t already insulated, wrap it in some old towels immediately to prevent it freezing.
Get foam pipe insulation
As soon as you can, get down to your local DIY store and buy some foam pipe insulation to wrap the condensate pipe in (just make sure to check it’s for external use). This insulation comes in a variety of sizes, so measure the pipe’s diameter before you buy.
Turn up the heat!
During extreme weather conditions, even proper insulation may not be enough to prevent the condensate pipe from freezing. It may help to temporarily run your boiler with the boiler thermostat set as high as possible for as long as the cold spell lasts. But if you continue to experience problems, it’s best to call out a qualified boiler engineer for help.
Cover your drain opening
Add a leaf guard over the open end of your drain to remove any wind chill. This will reduce the chance the water in your condensation pipe is exposed to sudden drops in temperature—meaning it’s less likely to freeze.
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.
HomeServe’s nationwide network of Gas Safe engineers are here to help. Simply get in touch, safe in the knowledge you can count on us to keep you feeling toasty this winter.
Video Transcript
- During extreme cold conditions, your boiler may develop a fault, this could be due to a frozen condensate pipe. A common symptom of this would be, the boiler may start to develop a gurgling noise, it will fail to start and if it has a display it will display a fault code.
- It’s easy to fix yourself all you need to do is pour hot water over the condensate pipe. So let’s get the kettle on.
- I’ve got my kettle full of boiling water, I’ve let the kettle cool down for fifteen minutes. It’s really important to do this so that you don’t hurt yourself and also so that you can’t crack the pipe.
- Most condensate pipes freeze near to the ground, so it’s simply a case of pouring the hot water over the pipe slowly.
- Now we’ve thawed the condensate pipe it’s time to reset the boiler.
- If the boiler fires up job done if not you may need to give us a call.
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