Frozen Condensate Pipe

In freezing conditions a likely cause for a faulty boiler would be a frozen condensate pipe. A condensate pipe allows your boiler to dispose of condensation outside, so inevitably the pipe is more exposed to freezing conditions.
Therefore, if your boiler doesn’t work or you can hear bubbling and gurgling sounds coming from your boiler, then this could be an indication of a frozen condensate pipe.

How to find the condensate pipe?

The condensate pipe can usually be found on an external outside wall and in close proximity of the boiler. The pipe is usually a white overflow pipe similar to that you may find on a washing machine or sink waste pipe.

What to do?

1. Locate the condensate pipe and check to see if it has actually frozen.
2. Locate where the frozen blockage is within the condensate pipe. This will normally be on the most exposed point of the pipe or where there is a bend within the pipe.
3. Thaw your condensate pipe to remove the blockage. This can be done by pouring warm water along the condensate pipe to remove the ice blockage. Please do not use boiling water as this can damage the pipe.
4. Once the ice blockage has been removed then switch the boiler back on. Please check the boiler manual and follow the boiler manufacturers guidelines.

frozen condensate pipe


If you have identified the pipe then you can take precautionary measures to ensure it doesn’t freeze, for example insulating your condensate pipe will help.

Need more advice?

To discover other types of common boiler faults, or get advice on other plumbing and heating issues including, how to isolate the mains water or temporally fix a leak, then please visit our guides page.

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