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« Last post by Cary Austin on January 04, 2024, 03:24:51 PM »
"152.76psi Pump Pressure (@25gpm) - 43.35psi Riser Head Pressure (100ft) - 7.97psi Riser Friction loss (1-1/4" ID @25gpm) - 31.81psi CSV DP(@25gpm) = 70psi CSV Outlet Pressure"
OK, I take it from the above statement that the "riser head" is the depth to water in the well. I also assume from the 25JS3S4 model number and the graph showing zero flow at 500' of head that this is the 3HP version? I will attach a curve.
If you are using 25 GPM that pump can produce 350' of head. Since it is 100' to water in the well, the CSV at the surface will see 250' of head or a back pressure of 108 PSI. Because the pump can build 108 PSI you can loose 38 PSI to friction loss and still have 70 PSI outlet of the CSV. However, with the CSV1A set at 70 PSI while using 3 GPM, the 15 PSI reduced pressure at 25 GPM will cause only 55 PSI to come out of the CSV1A. You can adjust the CSV1A up to make up for the reduced pressure falloff, but not the friction loss. By setting the CSV1A at 85 PSI while using 3 GPM and a 75/95 pressure switch setting, it will deliver 70 PSI out let at 25 GPM while the inlet side of the CSV is at 108 PSI from the friction loss.
Next thing is if that is a 3HP pump it really needs a minimum of 3 GPM to stay cool. The regular CSV1A as a 1 GPM minimum for 2HP and smaller motors. We can make it into a CSV1A-3GPM, which will have a 3 GPM minimum to keep the motor cool, which is also the rate of tank fill after all taps are closed. At 3 GPM that pump builds 500' of head, which is the same as 216 PSI. 216 PSI would then be the max pressure the pipe in the well will see. But you would loose 43 PSI of that as the water travels up the 100' from the static level in the well. That means the pipe at the surface before the CSV and the inlet or back pressure to the CSV will be 173 PSI.
This is all very possible with what you have. But with that size pump and 100' to water the CSV3A2T would make a lot of difference. With this 2" valve there would be no reduced pressure fall off and every zone from 3 GPM to the max the pump can produce would be at a constant 70 PSI as that is the setting of the CSV3A2T. The inlet pressure to this valve would still vary according to how much water is being used. The inlet pressure to the CSV would be 173 PSI when using 3 GPM and 108 PSI when using 25 GPM. But there is only 3 PSI of friction loss which will allow you to use larger zones up to about 30 GPM before you start losing any pressure on the outlet of the CSV.
It would be great if you ran it with the CSV1A for a while then switched to the CSV3A2T. It would be easy to document the difference and night and day to see. Working less than 15-20 GPM with the CSV1A you are not getting into the maximums for that 1" valve. But anything higher than 20 GPM is pushing it for the CSV1A.
The CSV3A2T is a 2" valve that uses the CSV1A as the pilot control. If you do switch it out you will have a spare pilot for the CSV3A2T. Being pilot operated and a larger 2" valve is what lets the CSV3A2T have so much better flow characteristics than the 1" direct acting CSV1A by itself.
Thanks for making me explain all that as some of this stuff needs to be written down, not just in my head. Lol.
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