CSV or VFD for shared well

[Brett Jenson]

I am needing to install a new well pump.

the pump would shares with my neighbor.

Static water level is 185’. Pump is 90’ from the house and the last well test said the well was capable of 35 GPM.

I definitely want a system with constant pressure. I like simplicity of a CSV but they pump guys in have met with have talked about “dirty” power and other things that are bad for a well pump and say that a vfd will protect this. The pump guy actually priced out a cycleguard. Is it worth asking him to do a CSV?

Should I do a VFD or CSV?

If I do a CSV, should the valve be installed before the neighbor t’s off the water line or after it does?

 

[Valveman]

Constant pressure is a good thing. VFD or CSV are the only two ways to get it. The constant pressure is the same whether you use a simple Cycle Stop Valve that will make the pump and system last several times longer than normal or spend 3-5 times as much replacing and maintaining a VFD over the same amount of time.

Cycle Stop Valves have been replacing VFD's and making pumps last longer for 30 years. The patent on CSV's expired many years ago, so Flomatic should be able to make a good copy. However, I have about 20 Flomatic valves on my desk as we speak. They are new and did not work properly, so the installer wanted to know if I could make them work like a Cycle Stop Valve. I will probably try to help as I hate they are not making a good copy of the CSV. I think some installers use those so they can say, "see they don't work, I told you that you needed a VFD".

CSV's are guaranteed to work. Even though or especially because there has never been a single pump damaged by a CSV, we also guarantee to replace any pump damaged by a CSV. If you can get the same guarantee from Flomatic or from the VFD company then you don't need a CSV.

 

[Sponsor]

 

[Valveman]

Oh and yes the CSV would need to go before the first tee off. With two houses I would use at least a 10 gallon size tank. We make kits to install the CSV1A or the CSV125 before the first tee and the manifold with the tank goes in a house or somewhere else. Look at the PK1AM-10 and the PK125-10

 

[Brett Jenson]

Thanks @valveman !

I have a large tank I think 80 gallons. Should I keep it, or switch to smaller? Is 10 gallons sufficient or is bigger better? Space isn’t huge concern.

Also, I’ve read a little about back pressure, how do I plan for this?

 

[Bannerman]

The only reason for a large pressure tank is to reduce the frequency of cycling by the pump.

While a large tank maybe utilized, the CSV will prevent pump cycling as it will restrict water flow from the pump to match the actual rate of water use.

Your 80-gallon tank will hold approx 20-gallons water between the typical 40/60 pressure range for most well systems. In using that 80 gallon tank with a CSV, 20-gallons water will need to be consumed to cause the system pressure to drop from 60 to 40, to cause the pump to become activated. Once the pump is activated, the CSV will then restrict flow to maintain typically 50 psi downstream for as long as water continues to be utilized.

As a 10-gallon pressure tank will only contain approx 2.5 gallons over that same pressure range, then only 2.5 gallons will need to be utilized before the pump is activated to cause the CSV to deliver 50 psi to either/both homes.

 

[Valveman]

Thanks Bannerman. To simplify a little, there is nothing wrong with using the 80 gallon tank with 20 gallon draw with a CSV. The only negative is that you have to use all 20 gallons as the pressure decreases from 60 to 40 before the pump starts and the CSV starts delivering 58 PSI constant. Set ting the CSV at 58 PSI is needed to get only 2 minutes of run time to fill the large tank. If you have a good tank use it. When/if it goes out don't waste your money on any larger than a 10 gallon size.