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nolljef

New Member

1

Saturday, June 11th 2005, 9:51am

Sufficient pump size?

I'm currently using a Sears Craftsman 1hp shallow well pump for watering and am wondering if this will suffice for driving an inground sprinkler system. I think I get around 15-18gpm at ~40psi and have .5 acre lot size. Using this system I can usually use 2 oscillating and 1-2 gear driven at a time off of 3 hoses. I think if I use around 5-6 zones I can pull it off but before I start investing I'd like to make sure that I'm not trying to something that can't be done.

Can anyone confirm or let me know if I'm going down the wrong path? Thanks,

Wet_Boots

Supreme Member

Posts: 4,060

Location: Metro NYC

2

Saturday, June 11th 2005, 12:44pm

Your shallow well pump will do okay, but for a good sprinkler system on a shallow well pump, don't use too small a pipe diameter. You have little enough pressure to begin with, and you want to make an extra effort to avoid pressure losses.

RidgeRun05

Supreme Member

Posts: 314

Location: USA

3

Saturday, June 11th 2005, 5:06pm

I am with WetBoots, make sure you use a large enough diameter pipe because of your lower pressure.
Tony Posey
Ridge Run Landscapes

nolljef

New Member

4

Sunday, June 12th 2005, 5:24am

I just did the 5gallon bucket test and assuming I did it correctly I get just over 10gpm at 40psi. This isn't nearly as much as I was hoping for.

The way I tested is I had two hoses coming out of the pump, one at full and then I adjusted the other until the pressure was at 40. Then I timed how long it took to fill up the bucket.

10gpm seems kind of low, I don't mind the longer runtimes but that could be a heck of a lot of zones.

What kind of heads should I be looking at to give me good coverage at the expense of gpm and runtime?

For the $300 or so is it worth trying out a larger pump. The only drag with that is that I'd probably have to wire for 220.

Wet_Boots

Supreme Member

Posts: 4,060

Location: Metro NYC

5

Sunday, June 12th 2005, 6:56am

Is this your pump? http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=LAWN&pid=08302522000&tab=spe#tablink
Note that you already need a 20 amp circuit for the pump. A good cast-iron-case 3/4 HP shallow well pump could outperform that Craftsman 1HP on that page. That being said, you could get by with 10 gpm for half an acre. Most shallow well pumps will deliver more water at a lower pressure, so you might consider the implications of a 30 psi water supply - Right now, I'm looking at an old catalog, showing a 3/4 HP high-capacity cast iron pump that delivers (ten foot suction lift) 11 gpm at 40 psi, and 30 gpm at 30 psi. Unfortunately, to make best use of a pump like that, I would need a mainline pipe size of at least 1 1/2 inches. (and an equally large suction pipe - no well points can be counted on for 30 gpm) As for sprinklers that work at less than 30 psi, there are only two types I've worked with that could handle such low pressures. (Rainbird's R-50 ball-drive rotor, and their Maxipaw impact heads) - the R-50 is about as good as it gets, once you figure out the adjustments, and accept the shorter spray distances you get at less than 30 psi. The Maxipaw is less reliable, but capable of long life, and is especially good for pumping 'dirty' pond water.

nolljef

New Member

6

Sunday, June 12th 2005, 7:55am

Yup, that's the pump.

So would something like this be better?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3191&item=5981170211&rd=1
or
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=61574&item=7522688511&rd=1

actually, this one caught my eye
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=42132&item=5981356386&rd=1

What's the advantage of the pressure tank? Also, while I'm asking what's the jet package on the craftsman to orther than provide a foot valve.

I'm guessing my well is about 20' to water (it was here when I moved in and can't find any docs on it anywhere), at least that's what 10gpm shows it to be on the sears chart so is there a way to figure out what I would get when all they give is gph?

Sorry for all these pump questions but the guys at sears are clueless on their own products and I have had a hard time finding this stuff out.

Wet_Boots

Supreme Member

Posts: 4,060

Location: Metro NYC

7

Sunday, June 12th 2005, 12:18pm

Save your money. Those are toys compared to the real thing. The higher the pump has to lift the water, the less flow and pressure you will get. Consider just working with the 10 gpm at 40 psi. It is adequate for the job, unless your soil is pure sand.

The 'jet' is for coaxing higher pressure (or higher lift) from a pump. For deep well use, there would be two pipes running from the pump to the well, and the injector assembly (containing the jet) would be located down below the water level in the well. The pump pushes some water down into the well, through the injector assembly, which allows the pump to bring up water from much deeper than a shallow-well pump can.

RidgeRun05

Supreme Member

Posts: 314

Location: USA

8

Sunday, June 12th 2005, 6:50pm

I personally wouldn't buy those pumps off Ebay. Most everything on there of that sort is cheaply made and probably won't last you more than a couple years. Invest in a high quality durable pump.
Tony Posey
Ridge Run Landscapes

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