On Thu, 27 Aug 2009 22:48:53 +0100, Stephen wrote:

On Thu, 27 Aug 2009 09:03:34 -0500, Jules
wrote:

I'm taking the other option, and running *all* the drain into the water
barrel, then just having an equal-diameter overflow into the drain below.

What size pipes are you using?

It's all (without going out to measure exactly - it's raining! 3x2"
rectangular pipe here for downspouts.

For the spill-over to the drain I'll use 2" dia round plastic pipe (the
internal diameter of which gives slightly more area than the rectangular
3x2") - purely as the fittings are readily available in DIY places (as
plumbing / vent supplies) so I can cut a hole in the water butt and make a
water-tight* join.

* of course the curvature of the barrel makes this more difficult, so I
anticipate application of some goop or other to assist! :-) I suspect
aquarium sealant might be best, as with the barrel full the bottom portion
of the overflow seal will be submerged (and I don't think any of the
conventional DIY sealants are intended for continuous submersion).

The rectangular pipe will just sit slightly into the water butt without
being physically joined to it (although I'll make a regtangular slot in
the cover); it'll be secured to the wall just above.

I think I'll put some mesh right at the top of the downspout in the gutter
just to keep large items (leaves are the main worry) out of things -
I've got scads of glavanised stuff sitting around which should do the
job.

My problem is how to connect large
pipes to a butt. I have seen tank connectors for 15, 20, and 22 mm pipe
but nothing bigger. How will you connect 40 or 68 mm pipe to and from
the butt?

Interesting that there's no 2" equivalent (which is what, 50.8mm?)...

cheers

Jules