Two Submersible Pumps in One Well Bore

"... hope the bottom pump doesn't fail"

Of course it will fail first. How long have you been doing this stuff? And after the failed pump is repaired/replaced and placed back into service, it will fail again!

Where will the second pump be in relation to the existing pump?

I see no problems as long as neither pump is allowed to run dry.

I'm suggesting a

Grundfos 3-sqf-3 progressive cavity pump & an ac/dc converter for the maximum flexibility

The storage tank is going to be around 400 feet above the pump(s). The house is probably 150 feet below this location. The system will probably be able to run without a booster or pressure tank

How is the plumbing set up for a double pump ?

I would put the new pump below

as far as I can determine the existing pump is a diaphragm pump, that's about 3 years old

I haven't talked to the well guy directly yet

I'm trying to get the lay of the land 1st

Are you plumbing these in series? I may have mis-interpreted your OP, if you are.

So, two pumps of differing type and capacity running on seperate power sources.

If the diaphram pump fails the system quits working. Diaphram pumps are positive displacement, so no fluid will pass through unless it's alive and well.

Sounds iffy to me.

What would an ideal set up be? with these 2 pumps?

When I 1st heard the idea, my initial reaction was the same

I want to be able to make a sensible recommendation

400 feet is a lot of lift.

You'll need to tee the outputs of the two pumps together so that each has an unrestricted inlet. Don't feed the inlet of one from the outlet of the other.

Each pump will need a check valve at it's outlet. You could get away without a check valve on the PD pump outlet, I guess, since if it quits water can't backflow through it.

Hello friends ,

I m have a question . I live in south texas and my brother lives next door . We are wondering is

it possible to run dual submersible pump’s in 1 well so that we can have separate electric bills . Is

it possible ? If so what has to be done ?

Good grief - two brothers that don't trust each other.

Never mind the pumps. It's going to get interesting come inheritance time.

There was me thinking few look at old posts. Technically fine, but as the Civil War (anywhere/anytime) shows, not much gets worse than a feud between brothers. I wonder where the OP went with this quandry.

What are the diameters of the well bore/casing, each pump, and each discharge pipe?

What's there is all 3"

I believe the outlet is 3/4"

The present setup lifts about 300' & has a pressure tank, but no reserve other than that

The rest is yet to be purchased

I don't quite see how there can be much choice of hook up besides series

which would seem to increase the possibilities of catastrophic failure

but not having all that much experience with wells I figured I'd post a thread before making unsupported proclimations

There's too much about this I don't know. First, I was assuming that you have room to by-pass the top pump with a pipe and tee them above that point. Stop me now if this isn't true.

I'm not sure a check valve will help here, either.

I'm also wondering how a constant output pump will match up with a pulsed output pump.

Check valves always help

I'm hoping KevinM will show up after the DD comes out & lays down the more common scenarios

My initial thought was to replace the existing pump with a dc PC pump, 3 solar panels[can't find the link right now] & a ac/dc converter, that would turn the pump on if the tank got too low [say 1/3].

The customer doesn't think he needs the converter, which I'm guessing is a couple 100 bucks, The double pump thing is probably going to cost more than that in added parts & labor. There's a $100 worth of copper wire easy

I am not sure why the client needs two subs in one well. Usually it happens in areas where water is difficult to find or just good quality of water is difficult to obtain. Most people like their own water supply and their own well. The legal requirements for rights of way get more complicated if it is sent to different properties owned by different people. Why? is a good question to ask.

It really shouldn't matter the type of pump. However, I will say that the existing 3/4 submersible must be just barely able to provide any output. It is likely a multi-staged sub of 18 impellers or perhaps more. The pump would be a more expense pump than say replacing it with a 1.5 hp with less impellers.

If the objective is to provide water for other reasons such as a cattle water trough and power failures are common, then a solar pump makes some sense. I am not sure the total head (lift+friction+pressure) needed but most houses would require something greater than a 3/4 set at 250 feet and a static level of 200 feet as reported. The total dynamic head may be 400 feet as suggested by Lyn. Someone needs to get a better selection chart and determine what is required. If the reason for the solar pump is to augment the sub now installed, take a closer look at the existing pump. Is this pump just pumping to non-pressurized storage? If the second pump or solar pump is pumping to a separate location, the redirect can be made from the existing pressurized discharge line or from a properly selected submersible pump supplying both locations. Yes some common sense may save lots of money and operational woes. Standard submersibles are very reliable in most locations but can be subject to lightening failures even if they are installed with lightening protection. Lightening does strike the same location over and over. They are good for return business and usually insured.

On second thought, a 3 inch diameter pump may be necessary if the well is only 6 inch diameter (1.25 inch drop pipe plus wire plus 3 inch pump). An 8 inch well or greater would be better. Pipe OD may be greater and proper selection is also required due to dynamic head. More questions to find answers before proceeding with the project.

Seems obvious that folks with 300 foot 5hp wells would love a second 1hp well in the casing so that in grid down they can water the gardens with solar power running the smaller pump.

I am not a well person but I think my common sense can help here. Lets say you have a 6 inch well casing with a franklin 5hp pump at 300 feet below. You might get 80 gallons a minute and the pump would be connected to a 2 inch iron pipe. Everything is great because your fat utility connection easily provides the 60 amp starting 220 volt current.

Then the utility goes down, you cannot water your gardens so you die because you did not have the foresight to also have a 1hp well that runs at 10 amps 110 or 220 volts that a solar installation with panels, batteties and inverter could easily run. Or a cheap 300 dollar gas generator could run for a week till you are out if gas in an economic collapse and thus you die from no gardens.

So you want the 4 inch diameter franklin pump with its solid 2 inch pipe all sitting in a 6 inch casing. You know you can buy 1hp submersible pumps that will deliver 7 gallons a minute at about 290 feet and use 3/4 inch poly pipe. Those pumps are available in 3 inch to 3 and 3/4 inch diameters. So you know that there is room for that pumo either above or below the 5hp pump. If above you have to make space for it by having two angles on the 2 inch steel pipe to make room for the 3.75 inch pump before the two inch pipe returns to casing center. If the 3.75 inch pump is below you have to have the 3/4 inch or 1 inch poly pipe and pump hanger steel wire and electric cable go to the side of the casing to clear the 4 inch franklin 5hp.

With backflow preventors to share the 2 inch steel pipe it seems like the 1hp should be above the 5hp, with angled 2 inch at the side of the casing for 4 feet before returning to center. The plumbing is easy and has nothing to do with pitless adapters for coming out the side of a casing below level to prevent freezing. The 1 inch or 3/4 inch should then be iron, not poly, with a backflow preventor preventor that fits - easy since you have 4 inches. The two pumps do not flow thru each other, each has a backflow preventor of its own with the one inch pipe joining the angled two inch pipe as the two inch returns to casing center above the 1hp pump.

So the simple summary is you would be crazy not to do this because it will prevent death by starvation or needing a 60 amp 240 volt solar capability.

Because I am not an expert I will get a 5hp franklin and a 1hp, plumb it up and sink it 300 feet in a 6 inch casing to test what I am saying. Alternates would be to use ground water pump for the garden rather than deep aquifer water, but since the casing at 300 feet is already a $10,000 investment if course youvwant to use it and the shared pipe 1hp pump adds almost nothing to the 1000 pounds of 15 lengths of 20 foot 2 inch pipe.

Do not question the guys motives - he is trying to survive. I will do this project and test it before end of 2017. Advise me since I know nothing, but I am not duh!

I would just guess that a person who started with a big pump like 5hp at 300 feet has around 5 acres and sprinklers. 80 gallons a minute from a 5hp well would run 2 inch valves with 2 inch pvc going to about 5 hunter sprinkler heads. 6 runs like that would water a 100 by 300 foot field, one at a time.

So then this guy discovers it is not so easy to power that pump if the utility goes down or the bill goes unpaid. He wishes he had a 1hp backup pump for the garden irrigators and the house. A house does fine on 8 to 12 gallons a minute, but a big field does not. He knows 10 amps is no sweat for generators that cost $300 bucks, but 60 amps is in the $1000 range. But he will run out of gas in a collapse and die if he cannot water his gardens with solar.

I proposed a solution, but chances are it will not work for him, because there is a great probability his casing is 4 inch, not 6 inch. There will be a steel plate on the casing with the casing depth and diameter and the well depth. They only have casing till they hit rock or limestone so the casing depth matters not, the diamter is critical. Who can solve it for a 4 inch casing and 250 foot deep well? I decided I could solve it for a 6 inch casing, but 4 inch casings are common.

I was a bit duh! because on second reading his casing is 3 inch. Gadzooks, no room for anything.

I cannot help. Did he solve it?

Seems his pump is plenty small enough for solar, battery and inverter.

Please do NOT connect the pumps in series!

Provided both pumps are under water level that will be achieved when both are running, they should be OK.

The header tank could be fitted with a simple float valve so that whenever the sun shines, the tank will be filled. (Fit the pump with an over pressure switch just like a small pressure system.) If the tank is full, then the float will create a closed head, reach the cut-out pressure for the pump and it will not run until some water is removed.

Treat them as separate systems and all should be good.

BTW, solar panels should be on a 2 (tilt) position mast for winter/summer orientation.

I haven't ever seen a diaphragm pump that would fit down a 3" well bore, but maybe they exist. More typical would be a centrifugal pump with multiple stages suited to the head to be pumped.

From the lower pump (if two are used) the discharge pipe and power cable will probably interfere with insertion of an upper pump.

You could stay with just one pump, but use a DC-to-AC inverter to drive it when enough solar energy is available.

In principle, two centrifugal pumps in series could work, even with only one running. But I don't know how to get power past the upper pump for running the lower one, if the upper one occupies the whole bore. There are other issues as well.

what would those other issues be?

Too long a story until the other issues are resolved first (old business before new.)

If the well casing is 3" a 3/4"hp submersible pump will occupy almost all of the i.d. of the casing so no pump would fit below it since the power cable and discharge piping must have room to pass by the 3/4hp submersible.

Likewise, the cable and discharge piping of the 3/4hp submersible would not provide enough room within the casing for a pump to be installed above it.

The only possibility might be to use a jet pump with the suction point located above the 3/4hp submersible. This set up would require 2 pipes connected to the jet and going to the pump of the jet system. This would be a total of three pipes and one cable within the casing above the jet suction, perhaps possible room wise.

Always use check valves on the discharge of both systems so that there isn't' a possibility of one pump system back feeding through the other pump system. If that would occur it would at a minimum be a waste of energy if not destructive to the systems.

Good Luck, Old Salt

With all due respect, if as you say, you don't have that much experience with wells, why are you trying to solve this complex problem, which sounds like a fool's errand to me. On the other hand, you could be competing for an annual 'Rube Goldberg' award, if such an honor existed.

Diaphram pump, 3" well casing, 400' head? Give me a break!

You are not required to reply

If you have some technical details to discuss, offer em up...

not a Good answer, by any stretch of the imagination...

Thanks

just the kind of stuff I'm looking for

I'm seeing the pitless adapter, not the casing, so that is a relevant question for the pump guy, which is the same one who did the repair a couple of years back...

I still don't think the potential benefits, outweigh the complications

Just because you can do a thing, doesn't make it a good idea

Sorry, this is out of control.

It depends on whom you listen to.

I don't think the OP knows what he's got here.

Why would anyone put an axial pump in line with a diaphram pump?

Agreed; that would be the blinded leading the blinded, so to speak.

you Editor Crankshaft see that I'm on a fact finding mission

I suppose it's not completely clear, that my role is strictly advisory

A pump company will do the work in the bore

I'll probably be doing the install of the storage tank, the hook up at the pump house & the residence

You can run the system with one pump by using proper control panel in combination with collector, charging control box,battery,inverter,autochange over panel,motro control panel and bore well motor. In day time pump will run with solar energy and other times it will switch over to normal power supply.

Good idea on paper.. and it can work and be VERY productive.. however I believe in this case the cost will outweigh the practicality of it.

Dual completions are a great idea in DEEP wells, as practiced by the larger oil companies in wells of over 8000ft and deeper, where it takes over 4 days to replace a failed pump, so with a "Y Tool" and two small OD pumps and providing the casing is of sufficient size, two motors, two sets of pump, two protectors and two runs of HV power cables are installed in the well.

By installing two sets of ESP's the idea is that if one fails the second one will continue, thereby extending the MTBF and the next workover....hopefully over 3 years.

However..... what happens if the well conditions are such that BOTH pumps fails.. then even more time is lost (and production) while twice as much work is done to pull and maybe replace both pumps, so nothing is really gained. And that is one of the reasons that dual completions are being re-thought!

So how does that relate to you and your project I hear you ask?

If you are going to have a dual completion, I would first ask why?

At 250ft how long will it take to pull and replace the pump? Not very long!

If your client is looking for a eco friendly in-expensive (cheap to run?) pump system.. then yes use solar cells to run the pump during daylight hours to fill a reserve tank.. so during the hours of darkness... pump does not run.. there water in reserve tank for general use.

I am assuming that the pump/system installed can only produce a few hundred gallons per day.... having two pumps in one small well other than having a back up in case one fails, to me is not cost effective.

Did you not say you will pull the first pump to install the new pump?.... So pull the old pump, install a new one, that is of a higher efficiency, that can run on sunlight, fill up the reserve tank during the day and the pump can rest at night.

The problems you might have with trying to install both pumps... not enough room in the well for the discharge pipes (plastic/flexible/metal??), then there is the cable!

In a small bore well you might damage the first cable by installing the second. Non return valves.... with only one pump, these might not be needed.. less expense! What you cannot do with a dual completion is run both pumps at the same time, as you will empty the well.... that in itself is not big problem, as the well will fill up again, however running a pump without fluid, you will damage, if not burn the motor/pump.

Going full circle.... "Why!"

Why run two dis-similar pumps in a such very small well? I would be really interested to find out why.. or is it a sales ploy?

The customer has money now & want to become more self sufficient for the future when he has less resources

My initial advice was replace the present pump [he said diaphram] with the Grundfos PC

Most pump companies in this area will buy old equipment for resale

The location of the proposed tank is far enough above the point of use to have usable pressure

If he wants backup when the power goes out, then I'd just use the AC pump that's there. Wire the pump to run from a DC/AC inverter that has a built in transfer switch. There are switches such as this that also have built-in charge controllers so you can charge the batteries when running on AC and switch converting to AC from the batteries when the AC power goes down. Much cheaper solution.

that will work too!

But I still want to know WHY??

The customer has this idea, that 2 pumps are better than one

He also has this aversion to converters & charge controllers

I think I can argue against this option more effectively now

In the end he can spend his money any way he wants

Is there wind in the area? It's quite good for this sort of thing. You can even balance out the head.

The well is down low on a tree covered hillside

He would like to do some wind generation

I probably need to do some data gathering from some of the different locations on the property. Any suggestions for cost effective data acquisition technology

My seat of the pants impression is that the best wind [& sun] is about where the water tank is going at the top of the hill

Data acquisition is fairly cheap and easy via any of the 'weather stations' on the web that have some inbuilt memory. And ideally a USB interface to down load data.

I wouldn't bother with 'wind generation' - as in then run an electric pump.

I'd just go straight 'traditional' mechanical.

Counterbalancing for rod and head means there is no 'lift' to constantly over come via power.

But perhaps this is too 'low tech'

I had suggested an areomotor, customer claims not enough wind at the well location

which is why I asked about DA options

I'd buy more tank & make hay while the wind blows, as it were

The ongoing maintenance is probably the lowest of any other option...

My last word is _{no, really, this will be the last word} these two pumps are not compatable, end of story.

Cheers.

I want two pumps in one casing too. My 5hp 310 foot grid connected pump would be a 60 amp start current, 80 gallon a minute 2 inch pipe thing. It is great. But for grid down all my gardens would die and so I presume I might starve. But a 1hp well would be a fine solar powered backup, or could be powered with a cheap 300 buck dual 15 amp generator. I am sure 10 amps would handle the 1 hp pump.

Has anyone solved this or do I spend 10k and drill another well? I take no grid, no gas, no deisel backup water for gardens seriously. My 5hp is a franklin electric 240volts with contactor box and well relay.

If I am pulling the 5hp to replace it, can two pumps and casings be lowered at the same time to avoid wire/ pump pipe collisions? Can a 300 foot 1hp well use polypipe, unlike tge,2 inch steel on the 5hp.

Laugh at the complexity, but survival on solar is the goal, but only when the grid fails.

Of course in the usa the grid fails everyday for folks. Just don't pay your bill and see for yourself. Want your gardens dead because you had a rough month?

I have done this and it works fine. Don't run the pumps in series, parallel until out of the well bore. Assuming each pump (and panels for the DC) are sized to supply enough water, then one can be left off and back-up the other.

Sorry Kevinm, It's more or less what you stated!

No problem Truman and it is good to have someone concur with your own posting. I would recommend the Siameseing of the drop pipe just to prevent the tangling potential. I am not sure if there exists siamese piping (not the smoking kind) for drop pipe that could be used in well applications. The pumps could be forced to rub on the well bore hole unless they are real careful in the installation. That rubbing could cause issues down the road. Perhaps torque arrestors installed just above each pump would help prevent the rubbing. Finally, yes a 10 inch well would be better but unusual for a domestic well. Cheers and nice chatting.

A 10" steel casing seems to be the norm here in Southern Spain so I made a bit of a wild assumption! Anyway, it's all fodder for Garth to use

Thanks MTB [ & everyone else ]

more good stuff

I feel like I can have a coherent conversation with the pump guy now

It's not possible to have a coherent conversation with this particular customer, he's full of Hobbity goodness. Sustainable this, Renewable that

Occasionally I can make him see logic...