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". 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.
--
Definition of a camel: A horse designed by a committee