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View Full Version : Using a centrifugal pump to irrigate from pond


BrendonTW
08-22-2011, 06:56 PM
I think I would like to try to irrigate my dads 2.5 acres using a centrifugal pump pulling water out of his well-filled pond. If I can get 50-100 GPM rather than 22 which is what our well gets, I can use less wire, possibly fewer valves, and bigger heads with bigger nozzles. The pond is pretty clean, and the intake will have a filter on it and float elevated within the body of water.

I have found centrifugal pumps from $800-$3000 which will provide 60-100 GPM at 50-200 PSI.

Can you all give me some "look-out-for's" or reasons to not do this. Also I am looking for a good brand pump or an anticipated approximate price range.

Thanks.

Sprinkus
08-22-2011, 07:00 PM
Is the electrical supply close enough and large enough to handle the new pump?

BrendonTW
08-22-2011, 07:02 PM
Not really sure. Yes there is one close by, but I'm not really sure what we'll need as far as line size. Running a new line isn't a big deal because it's only about 30 yards from the house connection.

Wet_Boots
08-22-2011, 07:19 PM
I think you don't use a straight centrifugal pump, because their efficiency peak is at a very low output pressure. You would have an easier time using a jet pump, with system flow maxing at about 25 gpm, which is plenty of flow for 2+ acres. You also save money by running a 1 HP jet pump versus a 2 or 3 HP centrifugal.

BrendonTW
08-22-2011, 07:58 PM
Well I could get almost 25 gpm straight out of our well. I want to accomplish 50-100 gpm for bigger zones or bigger heads. What would be my best option for doing this? I know that generally we would not do this for a 2-3 acre lawn, but I would like to do this on my dads place to get a new experience in with drawing te water from a pond.
Posted via Mobile Device

AI Inc
08-22-2011, 08:02 PM
K.i.s.s...........

Mike Leary
08-22-2011, 08:05 PM
I want to accomplish 50-100 gpm for bigger zones or bigger heads. What would be my best option for doing this? I know that generally we would not do this for a 2-3 acre lawn, but I would like to do this on my dads place to get a new experience in with drawing te water from a pond.

A new experience is what you're gonna get when the pricing comes in. :dizzy:

BrendonTW
08-22-2011, 08:14 PM
Well and that could certainly change how we do it. What extra costs do you anticipate I'm looking at? Just the electric and pump? Do you have an idea of what I could be planning to spend on a pump?

Wet_Boots
08-22-2011, 08:16 PM
I once devised a 30-40 gpm system to run from a 1 HP straight centrifugal, but it would only work with way-oversized pipe feeding an entire one-third-acre lawn as a single zone. Nice exercise, but not practical, or economical.

There is no useful experience to be had with using a straight centrifugal from a pond. The reason is that there are no sprinkler heads this side of a Maxipaw that can use the low-pressure water put out by a centrifugal. When you see a straight centrifugal pumping from a pond, the odds are very good that the pump is wasting electricity by operating at a higher output pressure than can be had at its efficiency peak. A 1 HP jet pump way outperforms a 2 HP straight centrifugal at pressures needed by standard rotor heads.

BrendonTW
08-22-2011, 08:18 PM
Thank you for the information! Very valuable. So I'm presuming that Jet Pumps are quite a bit more expensive. Can I get a jet pump that will match what I'm looking for for flow rates?

Wet_Boots
08-22-2011, 08:24 PM
Jets will top out in the 20+ gpm range, and they do cost more than centrifugals. If you really want to amp up the flow rate, at useful pressures, you wind up with a submersible in the pond.

BrendonTW
08-22-2011, 08:50 PM
That was my initial plan, but a centrifugal seemed more convenient. But not if I can't get what I need from one. What about a centrifugal with a booster?

Wet_Boots
08-22-2011, 09:14 PM
Sure, but you are burning money for no useful result, so why bother asking for professional advice? You would be just as relevant by using a 1 hp centrifugal to pull 40 gpm, and running it through 3-inch pipe to feed all-brass popup sprays operating at 20 psi.

If you had to get 50+ gpm from the pond at useful pressures with above-ground pumps, a centrifugal in series with a second centrifugal would work.

regularguy
08-22-2011, 10:37 PM
http://www.drillspot.com/products/66606/Dayton_2PC30_Booster_Pump

I have one of these pumps and it will do what you are looking for - or at least a couple of them will. You will need a foot valve and a good filter and a lot of water. I hope that is a big pond

Sprinkus
08-23-2011, 09:13 AM
A multistage centrifugal pump like the one linked is something I would use, unless there was 3 phase power available and a budget for a 5 HP pump.

Waterit
08-23-2011, 09:15 AM
Best bet is a submersible, a 3 or 5HP will give you plenty of volume and most importantly the pressure you'll need.

Sprinkus
08-23-2011, 09:23 AM
There is a 25 hp submersible inside this 10" pipe. System runs at 200 gpm/100 psi.
Easier to install something like this before the pond is filled.

Wet_Boots
08-23-2011, 10:01 AM
nice boot shot ~ here's a performance curve from the old Sta-Rite D-series centrifugal (http://www.starite.com/ResidentialProduct_sr_ws_cn_DHE.aspx), one of the few that can be set up with a 3-inch inlet. Using the 1HP model in its recommended operating range, leaves you sprinkling with Maxipaws or R-50 rotors. What we see are centrifugals operated at flows way below the recommended range, in order to have more pressure to feed common rotor heads, and that's a waste of money.

Kiril
08-23-2011, 10:51 AM
nice boot shot ~ here's a performance curve from the old Sta-Rite D-series centrifugal (http://www.starite.com/ResidentialProduct_sr_ws_cn_DHE.aspx), one of the few that can be set up with a 3-inch inlet. Using the 1HP model in its recommended operating range, leaves you sprinkling with Maxipaws or R-50 rotors. What we see are centrifugals operated at flows way below the recommended range, in order to have more pressure to feed common rotor heads, and that's a waste of money.

Are you reading the same chart I am? Looks to me like the 2 - 2.5 HP models will suit the guy just fine based on his desired flow and pressure requirements.

Given he hasn't provided even the first scrap of information needed to size a pump correctly other than how much water he wants to pump, I would say your statement is more than a little bold.

txgrassguy
08-23-2011, 10:58 AM
You can irrigate at the volume/pressure desired with a centrifugal pump but it will take
three phase power and probably at least 400 volts to accomplish.
I have, in fact, designed and installed a centrifugal irrigation pump to irrigate an 18 hole golf course in Asia. Wasn't ideal but it did work - the idea being to use what was at hand verse import.
However, in your situation, I would recommend a 2hp submersible, in a stand about two feet off of the pond bottom, with maximum pressure not to exceed 80 psi and volume limited to 30 gpm.
Remember, to utilize a larger pump requires larger mainline and lateral pipe as well as larger valving which will add significantly to the installed cost. This is an instance where bigger isn't always better.
Stay with a 1.5" mainline, all valving limited to 1" (yes I know 30 gpm flow is at the limit of these valves) and you can reduce to 1" lateral lines when flow rates decline to 18 gpm or so.
Pumps are much cheaper in cost, much more readily available, wire size is smaller and electrical operating costs are less too. Not to mention outdoor mounted controller and pump start relay being an off the shelf and not "engineered".
Install I-20's on swing joints with stainless steel risers unless live stock is present then I would use 4" schedule 40 pipe as a stand pipe with the lateral inside of the 4" pipe. Drill a hole in the 4" cap sufficient for the lateral to protrude about 6" or so then mount the I-20 on a male adapter. The 4" pipe should protrude at least 5' in order to prevent livestock from attempting to "drink" from the I-20.
You can then eliminate essentially all hand trimming around the 4" pipe by using soil sterilent then add road-base around the pipe. Once every 4 months or so simply hop on the atv and spray glyosphate on any weeds that the sterilent hasn't controlled.

Wet_Boots
08-23-2011, 11:40 AM
Are you reading the same chart I am? Looks to me like the 2 - 2.5 HP models will suit the guy just fine based on his desired flow and pressure requirements.

Given he hasn't provided even the first scrap of information needed to size a pump correctly other than how much water he wants to pump, I would say your statement is more than a little bold.Using the 2 HP DHG centrifugal at 50 gpm doesn't even get you much beyond 40 psi total head, and that goes lower once you deduct for suction losses, which leaves you little in the way of allowable losses through pipe and valves, to have even 30 psi at the heads.

Kiril
08-23-2011, 02:23 PM
Using the 2 HP DHG centrifugal at 50 gpm doesn't even get you much beyond 40 psi total head, and that goes lower once you deduct for suction losses, which leaves you little in the way of allowable losses through pipe and valves, to have even 30 psi at the heads.

It gives you 49.795 PSI total at your max recommended operating range (~ 115 feet head) which is close to 40 GPM. Without knowing details on pipe size, pipe run, elevation changes, suction lift, etc ..... (i.e. knowing your total head requirements) you cannot dismiss this pump as being a feasible option.

Wet_Boots
08-23-2011, 02:46 PM
the OP is talking 50 gpm minimum. Not 40, and even at 40 gpm, the output pressure of the DHG isn't anything that will let you run "big heads" like he was considering.

I think 50 psi head pressure is a bare minimum for heads beyond standard residential equipment, and 60 psi would be a more realistic minimum.

Kiril
08-23-2011, 02:55 PM
I didn't see the information required to calculate total head. Perhaps you can point it out to me?

Wet_Boots
08-23-2011, 03:33 PM
Huh? OP wants big flow and big pressure for a system beyond the usual PGPs or 5004s. I simply note that a centrifugal pump doesn't get you there.

(and most centrifugals don't get you into the comfort zone of standard system designs)

Kiril
08-24-2011, 10:00 AM
Yea .... OK Boots.

Wet_Boots
08-24-2011, 10:35 AM
So why don't you wind up that propeller beanie you wear as a thinking cap and show us all how a centrifugal pump is going to cover some acreage with 'big' sprinklers on it.

FIMCO-MEISTER
08-24-2011, 10:42 AM
Popcorn here! Sodas here!

Wet_Boots
08-24-2011, 10:55 AM
At ease, soldier. Even Poindexter J. Sliderule is going to take some time to find popup sprinkler heads that can throw 50 feet with less than 40 psi feeding them.

Kiril
08-24-2011, 11:33 AM
So why don't you wind up that propeller beanie you wear as a thinking cap and show us all how a centrifugal pump is going to cover some acreage with 'big' sprinklers on it.

Still waiting for that data you need to determine an appropriate pump. Do you have that info boots?

Beyond that we are talking about 2.5 acres here .... not 250. How "big" of a sprinkler do you need? How much money does the guy have to throw down for sprinklers? The Hunter G870 series rotor, a "big" turf rotor is listed at $255 per head, the G70 series at ~$120.

But then, what about Rainbird? The Falcon 6504 Series has a listed radius of 51 feet with a #10 nozzle consuming 8.1 GPM at a nozzle pressure of 40 PSI .... and for a fraction of the cost. Using the DHJ you can easily do it with these rotors. You could probably pull it off even with the the DHG, DHHG or DHH .... but without the data necessary to choose an appropriate pump we just don't know .... do we boots?

Wet_Boots
08-24-2011, 11:39 AM
OP wants big sprinklers and big flow to run from a centrifugal pump, and stated as such. Deal with it. Show us the way.

Kiril
08-24-2011, 11:51 AM
OP wants big sprinklers and big flow to run from a centrifugal pump, and stated as such. Deal with it. Show us the way.

The DHJ provides 81 GPM at 60 PSI discharge pressure with a 5 foot suction lift. Are you saying this is not enough to irrigate 2.5 acres?

The DHG provides 30 GPM with 5 foot suction lift at 50 PSI. Are you also saying you can't irrigate 2.5 acres with this pump? You don't know the first thing about how this system will be designed, elevation changes, system pressure loss, etc...... and yet you can definitively state there is no centrifugal pump that will work. You are a real piece of work bud.

Wet_Boots
08-24-2011, 12:08 PM
OP wants 50 gpm minimum, and stated as such. He wants "big heads" ~ make it happen with a centrifugal pump.

Kiril
08-24-2011, 12:12 PM
I see we are done here. Thanks for playing boots.

Wet_Boots
08-24-2011, 12:26 PM
OP says what he wants and you can only weasel the numbers, and finally submit that he needs a 5HP pump? Weak. Very weak.

I responded to the idea with a flat statement that there was absolutely no practical (that also means economical) way to achieve his posted desires, and you had to object to that statement, even without anything to back your position.

4v3etuIw-aM

Kiril
08-24-2011, 12:29 PM
Just for shits and grins .... since you are so hung up on the word "big" ..... using the DHJ you could run two Nelson 75 series "big" guns with a 0.45" nozzle at 35 PSI nozzle pressure (32 GPM) and a 154 foot radius. Is that a big enough sprinkler for you boots?

Wet_Boots
08-24-2011, 12:33 PM
Show us the popup heads that fit the requirements. Take your time.

Kiril
08-24-2011, 12:38 PM
OP says what he wants and you can only weasel the numbers, and finally submit that he needs a 5HP pump? Weak. Very weak.

What's the matter boots ..... having a problem with the numbers I posted on the Falcon? Are you saying you can't use one of the other pumps you posted to irrigate 2.5 acres using the Falcon rotors?

I responded to the idea with a flat statement that there was absolutely no practical (that also means economical) way to achieve his posted desires, and you had to object to that statement, even without anything to back your position.

I see .... so now we have a price limit? You are the one who is hung up on "big" heads that are silly expensive.

Your answer, as usual, was use a jet pump, which doesn't even come close to filling the OP's flow desires. Again .... thanks for playing boots.

Kiril
08-24-2011, 12:39 PM
Show us the popup heads that fit the requirements. Take your time.

Oh I see .... "big" isn't good enough .... but it must be a "big" pop-up. Already posted the numbers on the Falcon, are you blind? Did you stick your boot in your mouth again?

Wet_Boots
08-24-2011, 12:47 PM
You simply have no (rational) response to the flat statement that the OP's desires can't be met with a centrifugal. It stands as truth.

Kiril
08-24-2011, 01:12 PM
You simply have no (rational) response to the flat statement that the OP's desires can't be met with a centrifugal. It stands as truth.

Now that is just plain bullshiit boots. His requirements can most definitely be met with a centrifugal .... and not only met .... but would way exceed the OP's "requirements" providing he has the money to drop. I have better things to do than to argue with the inane ..... :waving:

Wet_Boots
08-24-2011, 01:27 PM
the OP also posted a dollar amount - a minimum dollar amount that cannot get it done with a centrifugal - do try to pay attention

Wet_Boots
08-26-2011, 12:10 PM
note to OP - you might try for half a loaf here. Forget pumping pond water, and go with the existing well, and see what you can do to make it run "big heads" which in your case will only be one notch above the usual residential stuff. Pressure is what you're after here, and you can adjust the pressure switch to have the well cycling in something like a 60-80 psi range (assuming you have a 100 psi rated tank or better. If the existing range is very much lower, you could cut in a PRV into the house feed, so they don't see the higher pressure. If codes required you to have an RPZ in the sprinkler plumbing, then you would have the cut-out pressure increased accordingly. At some point, you have to trade in the usual pressure switch for a larger one, in order to gain a higher pressure range (a standard Square D switch is spec'd at about 75 psi maximum cutout, but there is usually another 10 or so psi beyond that, before you run out of adjustment room)

The idea here is to get at least 60 psi at the sprinkler heads, and to run some zones with larger nozzles, so you get an idea of how things work with bigger heads, and the greater force of water they produce.

An in-between approach could be made by pumping your pond water with a Sta-Rite DSS4HG pump, which is a multi-stage pump that is a size larger than most any jet pump. It still won't give you 50 gpm with pressure to operate "big heads", but you can zone the system in a way to pick and choose the operating point you want on the pump curve. At 25-30 gpm, there's pressure enough to run the larger heads the way they were meant to be.

http://img192.imageshack.us/img192/7615/1056tc.jpg

regularguy
08-26-2011, 02:18 PM
http://www.starite.com/ResidentialProduct_sr_ws_cn_DSS4HG3T.aspx

In case anyone is interested.

Boots, I am wondering if you have one of these pumps installed someplace? I've noticed that you have mentioned it in several posts (some very old) and I'm curious about the pumps performance. I am a little concerned about the pumps plastic impellers and ports, but I am equally impressed by the amount of head that the pump can develop. Typically I lean towards brass impellers in high pressure applications as I feel they are inherently more robust, still I'm interested in your thoughts and experience with this pump.

Wet_Boots
08-26-2011, 02:38 PM
Some others here have used that pump, I'm certain. My own pond work never needed more than 25 gpm, so I could get by with a jet pump. I also liked that a jet pump can't create more than 80 psi in a deadhead situation, which matters when you have poly mainlines. No question but that pump stands out as delivering great pressure for sprinkler systems, but maybe it has its own issues, and those that have installed one can recount them.

Plastic impellers never seemed to be an issue with the Goulds pumps I favor. I think in the early days, the pump mfrs didn't want to spend money making molds for impellers they could machine from brass.