[Greenbuilding] Special Valve

[Speireag Alden]

Hi, Lile.

     Thanks for the reply.

Sgrìobh Lawrence Lile:

>   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?

     I'm storing a fair amount of water by conventional standards (two 
large pressure tanks), though not by the standards of people who use 
cisterns.  My conventional pump can certainly keep up (and then 
some), but the less it runs,

     . the longer it lasts and the farther its date of replacement,
     . the less power it uses, and the less electricity I buy from a 
nonrenewable source,
     . the more water runs through the coils around the passive annual 
refrigerator, thus making it work better,
     and
     . the more I have (while it's sunny) high pressure all the time 
for various household purposes

     These are all good things, and don't require additional pipe.

>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.

     Yes, but then I'd have to run additional pipe (I'm in a hard 
freeze climate up here in New Hampshire), which is a pain.

>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)

     A PT valve like that could be put pretty much anywhere in the 
system, but I've heard that once PT valves blow, they never seal 
right, and I don't want the system to leak water below the threshhold 
level.

     I'm willing to go with a battery-operated pressure sensor hooked 
to an electric valve on a low-flow line.  But I was hoping for 
something mechanical, and more graceful, which would let out only the 
excess, at a matching rate.

-Speireag.

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

-Speireag.