Frozen condensate pipes

6 Apr 2006
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United Kingdom
I found a thread on this subject dating from last January and wondered whether there have been any developments of ways to avoid this. I did not have a problem last winter, but the boiler went off (showing flame failure) on the day when we were leaving to spend Christmas with our daughter. Not only was the descending condensate pipe frozen, but the soakaway was also solid. I got the pipe cleared, draining about 2 pints of condensate from the boiler, reset the boiler and got it started and running. I had to leave the down pipe disconnected from the bottom section and diverted the drainage down a bit of guttering as a temporary measure until I could get the soakaway cleared. We went off, leaving the heating running on constant setting, with the thermostat set to 18 degrees.

When we got back 5 days later, the boiler was again off due to flame failure and the temperature inside the house was 8 degrees. The weather had turned milder that day and the condensate pipe was clear. I reset the boiler and it started again. It has run OK since. I have also now cleared the soakaway and reconnected the drain.

Firstly, the external pipe is 22mm and is insulated with the foam sleeve stuff. I have renewed the insulation with the thickest available. One suggestion I have heard is to use 32mm tube for the external drain. But if there is insulation material for such tube, I have not found it.

Secondly, I have considered trace heating wire, but that will not stop the soakaway freezing.

Finally, if I do fit the 32mm tube, how can I connect it to the 22mm pipe that comes through the wall? I have not found any 32 to 22mm adaptors.

Any suggestion will be welcome. I want to be able to leave the heating when I go away in cold weather with reasonable confidence that it will stay on.
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can you see any way of connecting to an inside waste pipe, for example the sink or washing machine waste?
There is bung style adaptor that converts your 21.5mm condensate to 32mm. Your local plumbing merchants should have one. While you are at it I would recommend to go to 40mm, this is if you can't find a way to go internally which would be far better.

Andy :)
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No chance of going internal I am afraid. The sink and other drainage go through another wall well away from the boiler.

I should have realised this was coming as the patio did not drain during the first thaw as that drain was frozen. At that point I should have started looking at the condensate drain.

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