Even the most looked after boiler will struggle to function if its condensate pipe freezes. Luckily, it’s not a difficult job to put things right if it does happen. This handy guide will help you get your boiler up and running quickly and easily.
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 a condensate pipe?
Watch our video on how to thaw a condensate pipe
Check out our handy step-by-step guide below, or you can always read the video transcript.
If you suspect that your boiler condensate pipe has frozen, the following steps should help you get things back to normal quickly.
Remember, if you don’t feel confident when following this guide then you should contact an expert boiler engineer for help.
- 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.
- 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.
- Use hot water to thaw 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 (do not use boiling water as this can crack or damage the pipe). If you’re using a kettle, make sure to cool the kettle for at least 15 minutes once it’s boiled. Alternatively, you can use a hot water bottle or a heat pack to slowly defrost the pipe.
- 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.
- 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.
How to stop your condensate pipe from freezing
If your condensate pipe isn’t already insulated, wrap it in some old towels immediately to prevent it freezing again. 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.
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.
Should you pour boiling, hot or warm water on a frozen condensate pipe?
Do not pour boiling water onto your condensate as it may cause the pipe to crack. We recommend only pouring hot or warm water onto your condensate pipe.
Using a kettle? Make sure you’ve let it cool down for at least 15 minutes or more before using it (and check the temperature before you do!). Alternatively, you can use a hot water bottle or a heat pack to slowly defrost the pipe.
Be careful where you pour the water too – it may freeze and become a slip-hazard.
- 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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