How to thaw a frozen condense pipe.

By PaulS | Blog

Although the winters for the past few years have not been especially severe, there is always a chance of a few freezing days.

If the temperature remains at or below freezing point, some boilers installations may suffer from a frozen condense pipe.

If your boiler has stopped working and the following conditions apply –


  • The outside temperature is below freezing and has been for 24 hours or more.
  • The condense pipe from your boiler (white plastic pipe that connects the boiler to a drain or soak-away) is outside.
  • The condense pipe which is outside is 22mm (can happen with bigger pipes in very cold weather).
  • The boiler tries to start but quickly stops or locks-out.

There is an easy short-term solution in the video below:

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Please remember –

  • Boilers older than 15 years probably will not have a condense drain pipe.
  • Most modern installation (especially in the last few years) will either NOT have an external condense pipe OR increase the external pipe size to 1″” or more.