Boiler condensate drain slope

16 Mar 2009
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United Kingdom

I've got a question about the pipe for the condenstate drain from a condensing boiler.

This is an existing installation so the pipe is already in place. The pipe is connected after the condensate trap on the boiler itself and (at the other end) to the internal sink waste, downstream of the sink waste trap.

The overall drop is much more than 1 in 20 and at no point is the pipe higher than its start (i.e. at the boiler).

However, at one point (about 10cm below boiler), it angles up very slightly, before dropping again. My question is does this matter (I guess some condensate water will always be standing in the pipe at this point)?

The pipe is all internal (in a kitchen).

Many thanks for reading

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I dont think that it matters much.

However, I would still suggest that its corrected as standing water often creates a blockage because solids congregate and dont get washed away under gravity.


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