Condensate drain

[newshound]

Just been on my mate's garage roof, removing ice from his condensate drain. Hopeless positioning, pipe run is about 12 feet with the last foot inaccessible from inside because of overhanging eaves. I think what happens is that a plug of ice forms on the outside, sometimes it slides out until it hits the inside of the gutter (no scope to re-route over the gutter), at which point it all freezes solid. It would be difficult to get trace heating in there without removing tiles and felt, the pipe runs in a 2 inch gap between a floor joist and the wall.

Boiler is on gable end wall over the garage roof, I reckon the best fix would be to go out through that wall and live with it draining onto the felted roof.

My inclination is to drill the through-wall pipe so that it is draining down at about 45 degrees (the internal pipe has the usual slope of 10 degrees or so), and extend it out far enough so that it is not draining on to the felt to wall join. Might put in a bit of alloy plate or plastic sheet at the drip site to help protect the felt.

Cavity wall with polystyrene bead insulation. I'd drill from inside through a suitable vertical joint in the blockwork (outside is brick). I have long SDS drill bits of various diameters, obviously I would start small.

I'd wondered about using 32 mm waste pipe for this section rather than the usual stuff.

Any thoughts, comments, suggestions?

[tabbypurr]

go back to the beginning & start with a diagram

[newshound]

A 3d layout is better explained in words. The boiler is on the gable end wall. The current drain runs parallel to the wall, sloping down at 10 degrees. I am proposing to cut it near the boiler and add an elbow to take the final pipe out through the wall. I am thinking to slope this one down at around 45 degrees to improve the drainage and reduce the chance of gradual ice buildup in the cold, exposed bit. And maybe increasing the diameter.

[Roger Hayter]

Use a condensate pump near the boiler and a flexible pipe indoors to a reliable waste leading to the soil pipe.

[Jim GM4DHJ ...]

mine goes from the boiler in the garage into an internal waste pipe from the utility room so no problems with ice......

[newshound]

My own already runs indoors.

With the layout of this house, it's a long and awkward run to any waste pipes, especially with a boarded loft full of stuff. And a condensate pump is one more thing to go wrong.

But, thanks for the suggestion, it's worth considering. Does anyone recommend any particular pumps?

[Dave Liquorice]

Cut away the bit of gutter that stops the ice plug? The condensate will still drip/trickle into the gutter and away (hopefully). With a bit of luck you won't have to cut much away so there won't be any affect on rainwater carrying unless it seriously pisses down.

Donno how much condesate a (presumably gas) boiler produces. It's probably not as much as our oil burner which does IIRC up to a litre for every 750 ml of oil burnt and it consumes oil at 3.5 l/hour...

Either way there is a possibilty of this just building up on the roof, even if there is a decent fall. Weight? Place a bit of gutter to guide the condensate to the main gutter?

I think the regs have something to say about the size of exterior condensate drain pipe work. Fairly sure 32 mm minimum.

[Brian Gaff]

Its been all over the media that numerous condensate pipes have frozen. OK for those where its accessible easily but for everyone else its a nasty job usually outside in a blizzard on a ladder. I'd have thought a bit of forethought about this should be standard practice for an installer.This issue comes up every time it gets a bit cold. Brian

[F]

Local plumbers have been trying to outdo each other by offering helpful 'it's your condensate that's frozen' type posts on Farcebook.

One of them has included a photograph of what is, presumably, one of their installations. With a sagging 500mm long near-horizontal section of condensate pipe, it's almost guaranteed to be the first to freeze.

Not much of an advert for his services.

[David]

Ours runs under the first floor (boiler in airing cupboard) and drains into the internal soil pipe for the wet room. :-)

Serious other problems before that freezes!

Last house had the boiler in the loft but the condensate pipe was run down into the toilet and Td into the soil pipe.

Lucky to be able to do that.

Cheers

Dave R