On 11/27/2015 6:16 PM, Oren wrote:
On Fri, 27 Nov 2015 16:25:17 -0700, Don Y
wrote:

On 11/27/2015 3:54 PM, Oren wrote:

I guess my point was that the irrigation line "auto" drain valve and
the solar panel "drain" valve work basically the same. Water pressure
closes them - no pressure allows them to drain, either into the soil
or into the pool. What I call, maybe not correctly a "positive" drain
valve.

Yes. But I would imagine you'd have less "problems" (hard water
encrustations) with your "set up" than the configuration that
I'm employing.

We have the hardest water in the nation. See the "Lake Mead Bath Tub
Ring".

Dunno. Half of our water is well sourced. The other half comes down a
few hundred miles of concrete aqueducts, pipes, etc.

I've not had a problem in over a decade on the solar panel
drain valve. Maybe you worry to much; regarding the irrigation "auto"
drain valves under ground. Picky picky picky.

I'm not keen on creating "maintenance tasks". E.g., I felled ALL
of the trees on the property before I got old enough to make that
a "challenge". I pulled out the lawn so it wouldn't need to
be watered -- or mowed. Soon, I'll replace the roof and repaint
the house exterior -- those will be the last "big" chores I
intend to tackle.

(Well, I also have to haul 20T of stone into the back yard -- but,
I built an electric wheelbarrow to make that easier)