CSV for irrigation pumping from somewhat dirty pond water

[dbr1]

I am installing an irrigation system pumping from a pond reservoir. Water is drained from the pond by gravity to a 2 HP irrigation pump and then out to multiple turf and landscape irrigation zones.

The water is also used to supply hose outlets for non automated watering and other applications. There is a pressure tank and a pressure switch which starts the pump.

The pond is refilled from a canal intermittently. The water in the pond has intermittent algae blooms, particulate from plants that grow in it seasonally, also some sediment. It is screened prior to entering the pump but some debris gets in, not a lot. After the pump, there is a disc filter which effectively removes all particles and debris.

I would like to add a CSV to the system. As I understand it, a CSV will not work if installed after the disc filter, and the only place to add it would be directly after the pump, where there would be the potential that some debris/particles would enter it.

Which, if any CSVs would work in this application? Do any of the CSVs have a built in filter or screen for this purpose? Otherwise, what would be the best way to install a CSV in this setup?

[Cary Austin]

Hello
There is no problem installing a CSV after the filter, as long as the filter is rated for more pressure than the pump can build.  If you give me the pump info I can tell you how much pressure the filter will see.

However, many of our valves are designed to handle some grit and debris so they can be installed  before the filter if needed.

We match the CSV to the pump size, so if you tell me the pump info we can make this work.

[dbr1]

Pump is a Flint and Walling SP20P1

DETAILS:

    2 HP
    Dual voltage (115/230) motor
    Single phase
    60 Hz
    3450 RPM
    Cast iron pump housing
    Self priming
    Easy-access drain plug
    2" NPT suction
    1-1/2" NPT discharge


link to web page with performance tablehttp://www.flintandwalling.com/ProductDisplay.aspx?ProductId=324

[Cary Austin]

You really needed a jet pump, not a so called “irrigation” pump.  That 2 HP pump will only produce 48 PSI max at shut off, even with zero lift.  It is designed to give about 60 GPM at 30 PSI.  That would run 30, 2 GPM sprinklers, but they won’t spray very far at only 30 PSI.

That pump really doesn’t build enough pressure to work with a CSV, and barely builds enough pressure to even work with a pressure switch.  If 30 PSI is enough to work for you, we could set the CSV at 30 PSI and use a 20/40 pressure switch.  If you are going to use 60 GPM, you will need a 2” model CSV3B2T.

The best thing to do with a low head pump like that is to adjust the pressure switch to something like 26/46, so that pump cannot shut off when running a hose by itself.  But then you have to hope the pump doesn’t wear a little, the water level doesn’t drop a bit, or something else happens that will not let the pump build to 46 to shut off.  Setting the pressure switch so close to the pump deadhead pressure is risky, because if it can’t build to 46 to shut off for some reason, it will nuke the pump.

[martinclukey]

I need to pump water filter system from my lake about 100 feet distance and 20 feet up. A shallow well jet pump with a CSV, small pressure tank, and pressure switch would do it.

[Cary Austin]

A submersible would be better because you don't have to worry about priming.  But a shallow well jet will work if you can keep the pump fairly close to the waters edge.  The more lift in elevation from the water level to the pump the worse it is for a jet pump.  The longer the line you are drawing from the worse it is also.  A sub would be better because it is pushing water not sucking water.