Explanation of CVG?

I think it's called a CVG valve? It allows constant pressure to the houses water system? Can someone explain how they work?
At first I was thinking of the variable speed pump, but when I heard they make a lot of RF "noise" I though I would reconsider.
Hope I have the right initials.

Thanks for the correction and webpage link.

Are there national statistics how many gallons per minute an average household uses?

Not being a professional I'm not sure how to fill in the calculator which tells me which valve to use.

We'll have 2 bathrooms and a kitchen with dishwasher in our new house. Washer and dryer of course. Most of the time it will be just the two of us, but we probably will have company from time to time

CSV's are matched to the pump. You will need at least 5 GPM for the house but, more would be better if the well will do it. Then when you decide the size of pump needed, you can match a CSV to the pump. Do you have any information on the well itself?

It's a little convoluted but here's the deal...
The house is being built on a Mesa, 150' below is the well which is 600' deep. When it was drilled they said the output would be 1.5 gpm, so I put an 1100 gallon cistern 200' from the house site on top of the mesa. It turned out the I get quite a bit more than the projected 1.5 gpm as I tried to pump it dry a couple times and couldn't. So the idea is to pump the water up the hill in the middle of the night to keep the cistern full, then pump out of the cistern to pressurize the house. I am using 1-1/4" pvc in and out of the cistern. The pump level will lower than the cistern level (by inches) so there will be gravity feed to the pump. I am thinking of a second smaller cistern in the basement (before the pump), maybe 250-300 gallons and put some cartridge filters in between the two cisterns.

If you think the well will keep up with the home use, scrap the cistern idea and make it simple. That's what I would do.

bob...

Me too, then you don't have 1000 or more gallons of stagnant water sitting there getting nasty between the times you clean and sanitize the cistern.

And with a cistern you usually need water treatment to disinfect the water. So no more cisterns, you don't need another one and by the way it sounds, you don't need the one you have.

And if you still use the 1100 gal cistern, I'd put a submersible pump in it and a small pressure tank next to it and a CSV. I'd control the well pump with a float valve or float switch in the cistern and this pump with a float switch to protect it from running dry and turn it on/off with a pressure switch on the pressure tank.

That 1.5 gpm is the recovery rate gpm, not the volume of water your pump delivers.

If you know the static water level in the well, and the diameter of the well, you can figure the usable (storage) gallons in the well. A 6" well has 1.47 gals/ft of water above the pump inlet.