Found a wet floor underneath my boiler (Vaillant Ecotec Plus System boiler) installed 6 years ago. I tied tissues to each pipe, and can confirm that water was running down the outside of the 20mm'ish plastic condensate drain pipe.

I'd guess therefore that my condensate drain is blocked. The pipe runs from the boiler under the floor and ties in to a sink waste pipe via it's own u-bend. Whould that be a reasonable diagnosis?

I'm hoping tonight to pull the pipe joins apart and flush out the blockage. But I have a feeling that I'll discover that all the pipe joins are solvent welded. If that is the case, is my only solution for flushing out the blockage to cut into the pipe, and then add new couplings afterwards? Or are there other tricks for flushing this blockage out?

In general terms I also looked at my maintenance manual, and discovered that there's a condensate siphon trap underneath the boiler that needs to be removed, washed out and replaced annually. I don't think it's ever been cleaned, so this is something that I want to do and I have no idea if it has contributed to the leak in any way. Manual describes that the trap is a bayonet connection removed by turning anticlockwise. I tried removing the trap, but found that it was stuck. I tried pushing up and rotate (like a light bulb bayonet), but I'm wandering if there's a knack to this...

Check the joint where it tees into to the waste pipe first.

_________________
Dave

www.drlgas.co.uk

Here's a photo of the trap. The joint to the waste pipe is welded as well.



I managed to remove the siphon from the boiler. Very little debris - much better than the examples I've seen in other youtube videos.