Grundfos SP Pumps: "16S07-8" vs. "10S07-12"

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Bubba

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My new build that was discussed here last summer got delayed until now. So I'm back for some final recommendations regarding a specific pump.

Shallow well cistern (measured 32.5" ID) with approx. 5' (250 US gal.) reserve water in the cistern.
TDH=190-200' (60 psi system+ 20' static head to pressure switch + pipe/fitting/etc. losses).
Design peak demand = 10 US gpm
Design pressure = 60 psi (50/70 pressure switch)
Pressure tank = 10 US gal.
Cycle stop valve = PK1A

After all of the helpful information last year, I'm convinced I should go with a Grundfos SP pump (230v, 2-wire) with cycle stop valve. When I go to the Grundfos website and look at the charts (and also using their online tool), they recommend a couple of different options - either the Grundfos "16S07-8" (16 US gpm, 3/4 hp, 8 stage) or the Grundfos "10S07-12" (10 US gpm, 3/4 hp, 12 stage).

I realize I only need 10 US gpm, but the 16 US gpm "16S07-8" is physically shorter and would be easier to set the pump in the well horizontally, and therefore use more of my reserve water. The total length of the "16S07-8" motor+pump is 24.2", whereas the "10S07-12" length is 27.5", which I think would be tight with fittings to set horizontally inside the 32" ID cistern.

Is there any downside to going with the "16S07-8" pump vs. the "10S07-12"?

Also, when I look at ordering for example the "16S07-8" Grundfos has 2 different order codes. One version includes a "CSIR" type motor, the other version includes a "RSIR" type motor. Any advice on these options?
 

Reach4

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I think you are using cistern to refer to a shallow dug well, and the pump will supply pressure to the house? I think that is probably it.

You want to put the pump near the bottom, horizontally. Maybe you could go 30 or 45 degrees off of horizontal.

You would want a flow inducer sleeve in 3 inch plastic pipe. I have some suggestions if you will be shopping for suitable pipe.

The 5SQ pumps will supply a normal house nicely, so I would not go beyond 10. Will you have something that takes a high flow, such as a backwashing iron filter?
 
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LLigetfa

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Grundfos pumps have a good reputation but their 2-wire motors don't. Are you trying to avoid a control box?

You need fewer stages for a shallow well to avoid up-thrust and higher hold-back pressure and to keep the length short. My 9 stage 10S05-9 is 24.5 inches long. I think the 16S07-8 is about the same length. The 10S07-12 would be around 27 inches long.
 

Fitter30

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Csri motor capacitor start induction run more starting torque over
Rsir resistance start induction run
Since both are factory design. It doesn't if they both meet your specs
 

Bubba

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I think you are using cistern to refer to a shallow dug well, and the pump will supply pressure to the house? I think that is probably it.

You want to put the pump near the bottom, horizontally. Maybe you could go 30 or 45 degrees off of horizontal.

You would want a flow inducer sleeve in 3 inch plastic pipe. I have some suggestions if you will be shopping for suitable pipe.

The 5SQ pumps will supply a normal house nicely, so I would not go beyond 10. Will you have something that takes a high flow, such as a backwashing iron filter?
Yes, shallow dug well, and pump will supply water to a pressure tank at the house, using a cycle stop valve. Yes, I want to put the pump horizontally near bottom of shallow well, which is why the length of pump/motor is a limiting factor. Inside diameter of shallow well is 32.5". Grundfos "16S07-8" and "10S07-12" are both "SP" type pumps, NOT the SQ line (Grundfos has a stupid model numbering system).
 

Bubba

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Csri motor capacitor start induction run more starting torque over
Rsir resistance start induction run
Since both are factory design. It doesn't if they both meet your specs
OK, so when do you want each type?
 

Valveman

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SP series pumps use the 4" motors in two or three wire. The two wire do not require a control box, but as was said I also hear they are having some problems. The Grundfos three wire motors seem to be holding up better but require a control box. The CSV won't take the place of a control box or pressure switch. With three wire motor you can get the CSCR or CSIR control boxes. Both will have a start capacitor. But only the CSCR box has a run capacitor, which can help with voltage problems and can even reduce energy cost somewhat. Either the 10So7 or the 16S07 will work in a cistern. But the 16S is shorter, probably less expensive, and will have low flow horsepower characteristics.
 
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