[Greenbuilding] [BULK] Special Valve

[Lawrence Lile]

Coupla questions, Spireag:

  What is the purpose of topping off the house pressure?  Are you
storing any signifigant quantity of water?  Can your normal centrifugal
pump keep up?

If you delete the requirement for house pressure, then the setup
bvecomes simple - pump into your pond, with a good air gap to prevent
any possibility of backflow into your domestic water well. 

You could accomplish the house pressure switch with a pair of
electrically activated valves and a pressure switch.  It gets
complicated, and it is electric which wastes some power.  Could probably
be done at 12V though. 

A very simple way might be to rig up a P-T valve (from a waterheater),
with a one-way valve, like this: (excuse crude ASCII art)

______
|Pump |
-------
   |
   |
   |   ---------
   |   | P-T     |
   |___|Valve    |___________ Overpressure line to pond thru air gap
   |   |_________|
   | 
|----------------|
| one way valve  |
|  >>>>>>>>>>>>> |___________To house pressure
|________________| 


The downside is, P-T valves usually pop off at 150PSI, which means your
house would be pressurized at this level.  That's a lot of pressure,
many household items can only handle 80 PSI.  I don't know if a P-T
popoff valve will automatically reset, or if it is manual reset. If it
isn't automatic reset, this whole scheme won't work, and I don't know
that capability of a P-T valve to operate many cycles.  This is
definitely a hack.   

The one way valve is required because, once the P-T valve pops, there
will be no pressure in that line, and the house pressure would blow off
into your pond.  The one-way valve would have to be good quality, not
just a brass flap but something with a good seal, to prevent leaking.  

--Lawrence Lile


-----Original Message-----
From: greenbuilding-bounces at listserv.repp.org
[mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Speireag
Alden
Sent: Monday, September 25, 2006 4:06 PM
To: greenbuilding at listserv.repp.org
Subject: [BULK] [Greenbuilding] Special Valve
Importance: Low

Hallo, all.

     Sometime over the winter, or in early spring, I'll be installing a
small solar panel over my well head, which will run a small, low-flow
pump in parallel to my regular well pump (and higher up in the well
case).  I want the low flow pump to top off the house pressure, and
then, as it keeps running, drive the remaining water to the pond.

     In order to do this, I need a valve which will let water go to the
pond if pressure exceeds a given limit, but otherwise won't let water
flow in that direction.

     I called my local building supply, and they're not familiar with
such a valve.

     Can anyone here think how to do this?  (Preferably without power
consumption.)

-Speireag.

--
Leaves starting to turn
Anticipation shivers
Me as winter comes

-Speireag.

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