CSV and well pump questions

[Thomasb]

Hello guys. My name is Thomas and am building a house in southern Ohio. I'm getting ready to have my well drilled in the next few weeks and am looking for some opinions.

I'm a maintenance tech and work with vfds daily. I know the pitfalls of adding complexity to a simple system such as a well pump.

House is high on a hill and I'm expecting the well to be 350-400 feet deep. Based on neighbors water elevation.

Let's call it 350 for comparison sake. So I'm looking at 150ish psi to push the water up, plus 50 psi for house pressure... Right at 200 psi (460 feet of head).. I'm looking at grundfos well pumps, and a 5s15-26 looks to be a decent fit.. the nominal head is 495 feet. But if you install a CSV the pressure at the base of the well wirh with 1gpm will be 700 feet of head (305 psi).

Am I calculating things correct? Is PE pipe not an option with a CSV at Wells this deep?

BTW the house is a temporary "starter" home one bath, no crazy shower setups, trying to maximize efficency, hence the 5 gpm pump choice.

Comments, suggestions? Thanks!

 

[Valveman]

Yeah 400' is a little deep for poly pipe. Just the 400' depth is 180 PSI at the bottom, before the pump even comes on and builds the extra pressure. The 7S15 is a better choice from that depth, but it will still build 290 PSI. It doesn't matter how deep the pump is set, it is still only lifting from the water level. It is very common for a 400' deep well to have a static level of say 50'. This would mean you don't have to set the pump all the way down at 400'. the pump would not have to be large enough to lift from 400', and there would be much less back pressure and lower cost of materials. Get the well tested to see how many GPM's it makes and from what depth, then figure a pump.

 

[Sponsor]

 

[Thomasb]

Well they drilled it, 380 feet to water. I wasn't about to put 350+ feet of schedule 80 PVC in by hand. So they put it the pump and at their recommendation a 1.5 hp 10 gpm Berkeley pump. Static water level is 250 feetp 15+ gpm. pump is set at 360, made me a deal on a flexcon wr60r pressure tank (only way they would warranty the system).

My only concern is the 1.5 Berkely doesn't get to 0 flow til 275 psi. I know that at 1gpm it will be slightly less than that. If static is 250 ft and I use a 40/60 psi won't the feed line before the CSV be at 170ish psi? Is that ok on the piping system? Thanks for any help or advice you can give!

Thomas

 

[Valveman]

Because it is 350' to static water, you can subtract the 350' from the 580' the pump can build at shut off. That means the pipe before the CSV and the CSV will only see about 90 PSI. But because of the depth, the pipe at the pump will see the 250-270 PSI. Because the static is 350', the down hole pressure and pressure before the CSV will only be 30 PSI higher than without a CSV.

The size of the pressure tank has nothing to do with the pump warranty. Berkeley warranty says nothing about tank size. And the pump installer can't change the pump manufacturers warranty just because of his misguided opinion. A CSV will still work with a 60 gallon tank, it was just a waste of money and space. And now you will have to wait 4-5 minutes in a 2.5 GPM shower as the pressure drops from 60 all the way to 40 before you use up the 12 gallons in that tank, which will then start the pump and let the CSV get you to 57 PSI constant. Setting the CSV at 57 PSI constant is required to keep it from taking too long to fill the 12 gallon draw down tank to 60 PSI. But once you have waited for the tank to drain and the pump to come on, the CSV will give 57 PSI constant for the rest of the shower, even if you shower for a month. One good thing about the larger tank is that you will be able to see how much stronger the shower pressure is at a constant 57 PSI, than while the pressure isn't constant and you are waiting on the tank to drain.

 

[Thomasb]

The flexcon wr60r is only a 20 gallon tank. Idk why they call it that metric possibly... But they warranty the whole system for 5 years, and they won't back that up if you use a knockoff pressure tank that fails in 2 years and you short cycle a pump to death.

I have a question reguarding this comment "Setting the CSV at 57 PSI constant is required to keep it from taking too long to fill the 12 gallon draw down tank to 60 PSI." Can you elaborate on that, why does it matter how long it takes to fill the pressure tank back up? If the demand increases wouldn't the valve just open back up and maintian whatever it's set too? Thnaks for your advice!

Thomas

 

[Valveman]

The flexcon wr60r is only a 20 gallon tank. Idk why they call it that metric possibly... But they warranty the whole system for 5 years, and they won't back that up if you use a knockoff pressure tank that fails in 2 years and you short cycle a pump to death.

I have a question reguarding this comment "Setting the CSV at 57 PSI constant is required to keep it from taking too long to fill the 12 gallon draw down tank to 60 PSI." Can you elaborate on that, why does it matter how long it takes to fill the pressure tank back up? If the demand increases wouldn't the valve just open back up and maintian whatever it's set too? Thnaks for your advice!

Thomas

20 gallon tank only holds 5 gallons of water, which isn't nearly large enough for that pump without a CSV. Without a CSV, that size tank, even a good brand, would cause the pump to short cycle and not last very long. I wouldn't warranty my work with that size pump unless you used at least a 62 gallon actual size pressure tank, or a CSV with at least a 10 gallon size tank.

With the 20 gallon size tank you need a CSV setting of 50 PSI with a 40/60 switch to get about 2.5 minutes of tank fill time. It doesn't hurt anything if the CSV takes 12 minutes to put 12 gallons in a 12 gallon draw down (60 gal tank), but it is just wasting electricity. Yes the pump would just keep running if you open another faucet before the tank is filled, which is good. But your wasting electricity if you let it run more than 2-3 minutes waiting on someone to use water before the pump shuts off.