Selecting a pump for a cistern

[MillWeld]

I need to pump water from a cistern that collects rainwater for garden watering. The cistern is only 5 feet deep and I have installed a foot valve at the end of a 1" pvc pipe by which it draws water which is filtered and sent to a captive air tank. I then use the water via a garden hose just like my domestic water except it has its own hose bib connection. My present pump is inadequate - takes too long to charge the pressure tank and loses its prime too easily so I want to replace it. I am looking at

Surplus Center - 1/2 HP 115/230 VAC WATER ACE SHALLOW WELL JET PUMP

from the Surplus center. It is described as a jet pump which I undertstand uses the Bernoulli principle to pump water. I asked the tech service dept at Surplus Center if this pump would work with my foot valve as described and they said that it would. I don't understand how a jet pump can work in this application. Doesn't a jet pump have 2 lines into the well/tank? one pumping water down the well to a narrow orifice which draws in additional water for the return trip to the storage tank?

I don't want to buy another inadequate pump so I am running this question to the top. I want to keep my plumbing as is and use a pump adequate for it.
Bob

 

[clsathome]

You may want to consider the Simer "pressuremate" 3/4hp pressure booster pump in the Northern Tool catalog. I needed a solution to get irrigation water up the hill behind my home. I did not have enough house pressure to get water up the hill. The unit is ready to install out of the box. I installed it using simple pvc fittings with hose and irrigation line adapters. After installing this pump, I now have no problem getting drip irrigation to 40 6-foot spruce trees 500' up the hill!

 

[Kays Supply]

There are deep well jets and shallow well jets. The shallow well only uses the one suction. The jet is built into the pump. It takes several gallons through the jet to get one gallon out the discharge. If volume is need, a straight centrifugal might be a better choice.

 

[MillWeld]

I installed the pump I referenced above but never got it primed so it has never pumped much water. In trying to get it ready for this gardening season I have dug up the suction line in hopes of finding a PVC connection I overlooked solvent-welding but I found none. I have primed (I think) the line by slowly pouring water in the top of the pump to fill the suction line all the way down to the foot valve. The 1" PVC line slants down all the way to the cistern so there should be no air trapped in the line. Plug it in and pressure rises only to about 10 PSI and the pump runs continously and sounds like the impeller is mixing air and water. Pump housing gets warm. Water w/ air in it comes slowly out of the spigot. I have repeatedly "re-primed" it but get no results. Does know a trick to priming that I am missing? If it will help I will post pix of the setup.

Pressure switch is set at 30 on and 50 off. Air tank is at 28 PSI.

 

[tommu56]

Is it a self priming pump?

what kind of flow do you want?

Do you have a foot valve in tank?

A submersible well pump in the tank with a cross on the discharge with 2 18" of 1" pipe to stop torque and the center of pipe as outlet.

Self Priming Electrics - Self-Priming Utility Pumps

Maltz Sales | AMT Self-Priming Pump

 

[Egon]

What is the height difference between pump and tank water level?

How long is the suction line?

Does the foot valve hold?

 

[MillWeld]

What is the height difference between pump and tank water level?
Only 5 feet

How long is the suction line?
10 feet

Does the foot valve hold?
Yes. I have removed the footvalve via a union (which is above the water) for testing and it holds water and I have the same priming problems with or without the union. So the union does not leak.

Thanks,
Bob

 

[mjw357]

Sounds like you have a leak somewhere in the suction line.

 

[Egon]

Bob, try a larger suction hose, say 2?? inches. The pump information may have suction line sizing. It may have to be the same size as the suction side fitting.

Just run a line above ground as a check to see if that fixes the problem.

 

[MillWeld]

The leak defies location. How would soap help locate it? Air would be drawn in leaving no bubbles. I can get 10 PSI water pressure in the line after running pump. When I shut the pump off I see no water drops but 10 PSI is not much pressure. I talked to Water Ace company and they said a 1" suction line would be fine for such a short run. Here are some pix. There are a lot of connections because I have been making adjustments/changes.

(One of the lines in the trench is a drain for a water softener and has nothing to do with the pump. It is also shown in the crawl space pic.) There is a single 1" line, with part gray elec. pipe, to the footvalve. I know it is not supposed to be used for potable water but this cistern water stinks and will never be drunk.)