Model W 1.25 50-120 issues

[ChemicalScott]

Our cistern pump cycles every 10 minutes or so. The pressure tank (switch) loses pressure even with the discharge plumbing from the pressure tank is closed. There are no leaks so it must be losing pressure back through the CSV and into the cistern.

Do I need a check valve to prevent back flow or should the CSV also act as a check valve?

When there is demand for water, the cistern pump cycles even more frequently. Should the CSV hold the cistern output pressure constant and keep the cistern pump from cycling?

This CSV is about 9 years old. It has always cycled often when there is demand in the house. The pump has recently started to cycle about every ten minutes when there is no demand in the house.

This system has always functioned like a typical pressure tank system. Reading the CSV info now, it sounds like the pump should run more consistently under demand and not cycle as much as it does.

Does this CSV need to be replaced?  I am considering just removing the valve and installing a larger pressure tank.

Thanks,
Scott

[Cary Austin]

No the CSV does not work like a check valve.  The check valve on the pump is leaking back and needs to be replaced.  You probably just have the wrong CSV.  The standard CSV2W1.25 is made for 3-5 HP pumps and has a minimum flow of 5 GPM.  Your house probably never uses more than 5 GPM, so it is like the CSV is not even there.  A CSV1A would never let the pump shut off when using more than 1 GPM, while the CSV2W you have won't even work unless you use more than 5 GPM, which is why the pump is cycling.

However, we do make a 1 GPM seat for the CSV2W, and we could easily swap it out for you so that valve would work.  And I am just assuming here, what size pump do you have?

[ChemicalScott]

I think we have a 3hp pump. I replaced it recently and will check my paperwork when I get back to the house in a few days. Thanks for the info.