Proper installation

[Zdsmith]

Hello, I have been using csv for many years now, but recently have had several people suggest I change the layout of my irrigation pumps as far as the plumbing goes. Currently
I am running two 7.5 hp pumps each with a csv. I am pulling water from above ground stoarage tanks. I currently have them plumbed with a check valve on the inlet side of the pumps, but have been told I should move them to the output side. If I move the checks I don’t think I will have enough back pressure to satisfy the csv. Is this correct? I am not sure where I should have the check anymore. Guys tell me on input side I will encourage cavitation (which I have definitely seen).  Any suggestions?

[Cary Austin]

When drawing from an above ground tank I like a check valve on the suction side of the pump.  Just make sure it is not too small and you won't have any restrictions causing problems.  But the check could also be installed just prior to the CSV's and it wouldn't make any difference in back pressure or how the CSV works.

If you are seeing cavitation, like worm hole divots in the impellers, it is usually from working too close to the shut off head of the pump.  The pressure switch needs to shut the pump off at least 10 PSI lower than the max or shut off head of the pump.

But if it has been working with the CSV's "for many years", it is probably fine.  if it ain't broke don't fix it.