David J wrote:
On Tue, 01 Sep 2009 15:14:36 -0500, Jules
wrote:

On Tue, 01 Sep 2009 19:59:31 +0100, David J wrote:
They appear to be a simple T juction with no moving parts, or valves.
So why should rainwater, dribbling down all sides of the downpipe,
elect to enter the water-butt and not continue to fall under gravity?
I think they're more like the following:

from
gutter

| |
--+ |
barrel | |
--+ | | | 'cup'
+--| |--+
| |
| |

to drain

... there's a narrower small piece of vertical pipe in the middle. The
rain mostly runs down the inside edges of the downspout and collects in
the 'cup' section, where it's free to exit via the side pipe to the rain
barrel.

So long as the top of the barrel is at the same level as the 'cup'
then once the barrel's full, the 'cup' will also fill up, and
excess water then spills through the narrow central pipe and from there to
the drain.

cheers

Jules

OK - many thanks.

With your explanation above it does look feasible. It also explains
why the pipe to the butt has to be fitted horizontally.

DJ

Be aware their resistance to dead leaves is precisely zero