Shallow well far from the garden: Pump location question

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I dried my house deep well once while watering the garden, and did not like it. (It is a big garden, and I also have about 40 fruit trees and a raspberry field)
Sooo, I decided to try to use a well I found in the field. It is 3' in diameter, 13 feet deep with water at 4.5' from the ground.
Distance from the house to the garden: 175' Distance from the garden to the Well: 175' further (350' from the house)
I need to run electricity from the house to the pump, and almost had a coronary when I saw the price of 12/2 electrical wiring, so I'd like to try to minimize the lenght of the wiring, both for cost, ease of maintenance and minimizing power loss.
I bought a new 3/4hp shallow well pump, a "Central Machinery 02955 1" Cast Iron Shallow Well Pump" and plan to use 1" PVC pipe. I would like to locate the pump at the garden, meaning it would have to pull between 5' and 12' vertical up the well, plus 175' horizontal. I know pumps are better for pushing than pulling, but I would save 175' in wiring and hassles.
Is that a bad ideeyer? Why? Thanks!
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On 4 Jul 2006 20:09:31 -0700, with neither quill nor qualm, "Jeannot"

First off, I have one of their 1479 pumps and while it's not bad, it's not a self-priming pump. I had a helluva time getting it to pump in the first place, but now I know what "foot valves" are. <g>

No, probably not, but you'll still have to trench the wiring and piping all the way. Gonna rent a Ditch Witch or hire it out?
Another alternative is if you have a gas-powered generator. Hauling it out there once a week to power the pump for watering might become a real hassle, though.
One question: Do you use drip irrigation in the garden? If not, why not? People with wells need to limit their water use and that is not only extremely good practice, it creates fewer weeds and healthier plants on 50-80% less water. STRONGLY RECOMMENDED. I drip irrigate my entire 1/3 acre with a $200 initial investment and about $10/yr maintenance costs. I hate weeding and my plants/trees/shrubs love me.
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I agree with Larry. I think that drip irrigation should be an intelligent option for your garden. You won't spend too much water, and your trees & plants will receive the water just where they need it. I have one too in my garden (Spain), and it is so common here having the garden irrigated with drippers or micro-irrigation. I should recommend you visiting this website, you can see lot of different products, and you can make an idea of what is necessary:
http://www.plasgotirrigation.com/products.htm
I hope be helpful for you.
Larry Jaques ha escrito:

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Jeannot wrote:

Ed is correct. Just trying to prime that proposed set up would be a nightmare. Leave one air bubble in the pipe run and you get no prime. Also a shallow well pump will pull water a max of about 26 ft verticle (sea level). Not sure how much of the horizontal distance you are talking about would equate to verticle but...
Harry K
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Jeannot wrote:

I forgot to add this.
Do a pump down test on that well before investing money/time in wiring and piping. It may be too weak to use. You can do one with your pump plus a generator.
Harry K
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I never heard about drip irrigation, but it sure sounds great, I'll research it. If I go with drip irrigation, the flow is probably less important so I would be able to locate it in the garden.
My farmer neighbor who lived there for about 341 years knows the well to be very productive. And I really do not care about drying it, my house has its own well about 450 feet away.
I will trench the wiring and piping myself by hand, my wife and I managed a rate of about 3ft/min last time we trenched some PVC.
The pump manual claims it is self priming, well, I hope it is. If not, is there some kind of device/kit/mecanism I can add?.
Thanks for all your input!
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Just remember that there's probably only one aquifer. Exceed the recovery rate of the one well, and you just end up dammaging the well and your equipment.
Exceed the recovery rate of the aquifer, and you're in a world of hurt.
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That's valuable input. Would you recommend I install a float switch and a relay to shut the system off when the water level falls too much?
Goedjn wrote:

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you're going to use an 800 GPM pump to draw from a 13' deep well? i would sure run some pumping tests first. Sounds overly optimistic without even considering that you want to install the pump so far away and suck lots of air.
lee h
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OK Lee, I understand that I may be optimistic, but just saying so is not really helpful.
I understand equations, and that there is a relationship between flow and suction power, so please entertain me as to how the numbers lead to the conclusion.
As far as specs, please use the following: 898 GPM, 26' suction depth and 140' maximum lift.
Thanks.
lee houston wrote:

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Jeannot wrote:

You do have a point but there comes a point when it doesn't matter what the pump or suction power is. A pump cannot suck more than about 26ft lift no matter how it is designed. It is physically impossible and will pull a vacuum if it exceeds that approximate lift. Now does your long run due to pipe friction add any 'lift' to that approx 6ft? Don't forget to figure in any elevation difference.
800 gpm is seriously overengineered for irrigation. If it works, you will have to put it through a pressure tank or it will blow your irrigation equipment. If put through a tank, the pump will run for only a few seconds at a time - very bad for pump longevity.
My shade-tree plumbers brain says you will not be able to get the pump to prime over that distance.
Harry K
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898gpm = 15 gallons/sec. That's a lot of water to expect from a 3" by 13 foot hole. i'm just suggesting that you fire up the pump at the wellhead as a test before the effort and cost of permanent wiring and plumbing. i suspect you'll be sucking air in very short order. if not, you've got an underground cavern just a few feet underground :-)
lee
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lee houston wrote:

Ah, but the actual production from the pump depends on it's output. If it is only feeding one sprinkler it can't put out 898 gpm. The sprinkler is going to -try- to put out more but it won't be able to. His system pressure at the point of use will be 64 psi max ignoring any elevation difference and pipe friction loss. I would expect that pump to fail under such a design.
Harry K
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Thanks for your continous interest.
The well is not 3" in diameter, but 3', 3 feet. I figured 8' of water in there
The pump has an integrated pressure tank that looks like 4-5 gallons from the outside (I know usable volume is less).
There will be a minimum of 4 sprinklers connected to the pump with plans for 4 more.
Look guys, I paid $61 for the pump. Let's say I sell it, or it explodes during use. Would I be better off with a submersible pump at the bottom of the well?
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Yes
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Guys, thanks for your continued interest.

The well is 3', 3 feet in diameter. I figure 8' of usable water * 1.5 * 1.5 * 3.14 * 6 gal/cuft = about 350 gallons. I'm still looking for my sprinkler specs (I'll just measure it if I can't find the specs), but 4 sprinklers ought to take at least

Harry, the tank does have the reserve tank integrated, so I'm guessing the people who designed the system sized the pump and the tank taking into account a wide variety of flows.
In any case, I will take the many advices about testing the system before trenching the whole cheebang.
Say, if I loose my pump or it explodes, would a submersible pump at the bottom of the well be a better ideeyer? For sure, less maintenance and no priming hassles.
Thanks to all
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Jeannot wrote:

Okay, we are getting somewhere here. I suspect your pump specs are wrong. PUmp that puts out that much gpm with a 4-5 gallon pressure tank just does not compute.
You are correct that you aren't going to lose much if the pump does go tits up so why not use it.
4 sprinkler heads will use about 20 gpm max (5gpm per head - that is a bit high but good for ball park figuring). A pump putting out near 900 gpm will start and instantly stop as it will have filled the tank that fast. The hardest part as far as wear goes for a pump is the start cycle. That's why, if your specs are correct, I say your pump will fail in short order.
I can't even begin to picture a pump putting out that much volume being either available for $61 dollars or small enough to install without heavy lifting equipement as in cranes.
I have rethought one of my replies above. You listed 'max lift...' and I computed that as being 'max head'. I don't recall seeing 'lift' being used in pump specs before. 'Head' refers to the hieght the pump can push a column of water and is directly covertable to pressure output at .46 psi per foot. If the 'lift' is the same as 'head' for your pump, the pressure is just right for irrigation use. 60psi while a bit high makes impulse sprinklers run very nicely.
Of course after all my rambling here, I am still of the opinion that you aren't going to get the pump primed over that much distance. But then, why not try and if it works, great, you will have saved a bund of work and money!
Harry K
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Harry K wrote:

AAAARRRRGGGHHH! I just had a revelation. Your pump spec is GPHour, I have been reading it as per MINUTE. Now it makes sense. My bad. You can disregard almosst everything I have been saying except for the doubt about it priming.
Harry K
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That was my mistake Harry. I wrongly wrote GPM, it was 898 GPH. Sorry. Now I understand about the crane remark. And the short-time failure.
Could someone explain what a "foot valve" is and how it works? I looked for that info and found nothing so far. Just stores.
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