Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss external condensate pipe to sink or not? in the Central Heating Forum area at

  1. caroldd21

    caroldd21 New Member

    I have had some helpful comments elsewhere on how to minimise the chances of the condensate freezing in an external pipe so thanks to all. Trace heating is probably going to be too expensive but I am considering a pump though it doesn't help get to a point internally because of layout.

    Because of the siting of the boiler I am going to have a condensate pipe travelling down the external wall and then 500 mm out to a soakaway.

    The first choice is to keep it just above the ground for the last 500 mm run out (sloping away from the horizontal) to the condensate trap. Advantages I can see are that the pipe is accessible if it does freeze and I can see if the joint fails at some point in the future (acid leak would be near foundations). Disadvantage is that I get a trip hazard and would have to warn all visitors.

    Second choice is to bury the last near horizontal 500 mm a little or even deeper. It is probably less likely to freeze (?) but inaccessible to me if it does (how would you thaw it?). Secondly, if the joint near the house did ever fail would there be any signs I would notice? Would the concrete show it for example?

    I have probably had enough disturbed nights and it is hard when you know nothing about plumbing! Does anyone have any answers to my questions to help me make a decision?

    Thank you in advance
  2. Matthew Score

    Matthew Score GSR

    I always use condensulate xtreme for external condensate runs, you have to run it in 1 1/2 pipe and use swept elbows but it won't freeze until it's below -20 which doesn't happen to often in the UK.

    I would bury the soakaway pot 500mm away from the property and no less than 500mm from the surface to the top of the pot, no good the pipe not freezing if the pot is frozen solid.

    3/4 fill the pot with lime stone chipping, make sure you leave an air gap between the pipe and the chipping.

    Last edited: Dec 14, 2018
  3. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    had that freeze last winter, thought it was 11/2 waste at first then cut into it to find that :D
  4. caroldd21

    caroldd21 New Member

    Many thanks for your detailed reply
    • Agree Agree x 1
Similar Threads - external condensate pipe Forum Date
Options for tidying up external waste pipes Fittings & Pipes Jun 5, 2019
External pipework for Outside Tap Plumbing Forum May 27, 2019

Users found this page by searching for:

  1. condensulate xtreme

Users found this page by searching for:

  1. condensulate xtreme