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Thread: help sizing pump

  1. #16
    Moderator valveman's Avatar
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    As I have said before, Franklin motors have been shortened up so much that a HP is only 10” long. They claim the motor being so short doesn’t need a flow inducer sleeve as there will still be some circulation just 10” below the pump suction. This maybe plausible and I am sure it works, there is just not as much circulation as when using a sleeve. I believe as long as the motor is not sitting in sand or set below the perforated casing it will be good enough.

    The 3” pump is a good idea, but is considerably more expensive and spins 10,600 RPM compared to 3,450 RPM of the 4” pumps. In the Grundfos engineering manual they claim doubling the pumps RPM will shorten the life by half, and I believe this to be fact.

    However, the 3” pumps do not need a flow inducer sleeve. They actually have a little pump inside that circulates the fluid through the motor for cooling. The electronics in this type motor would not stay cool enough without this cooling system. The 3” pumps are also a little longer than 4” pumps, so you would not be able to get the pump intake set as low in the well with a 3” compared to a 4”. When your well is 130’ deep and the pumping level is 126’, the deeper setting of the pump intake is important.

  2. #17
    DIY Junior Member ndwolf's Avatar
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    Quote Originally Posted by valveman View Post
    As I have said before, Franklin motors have been shortened up so much that a HP is only 10” long. They claim the motor being so short doesn’t need a flow inducer sleeve as there will still be some circulation just 10” below the pump suction. This maybe plausible and I am sure it works, there is just not as much circulation as when using a sleeve. I believe as long as the motor is not sitting in sand or set below the perforated casing it will be good enough.

    The 3” pump is a good idea, but is considerably more expensive and spins 10,600 RPM compared to 3,450 RPM of the 4” pumps. In the Grundfos engineering manual they claim doubling the pumps RPM will shorten the life by half, and I believe this to be fact.

    However, the 3” pumps do not need a flow inducer sleeve. They actually have a little pump inside that circulates the fluid through the motor for cooling. The electronics in this type motor would not stay cool enough without this cooling system. The 3” pumps are also a little longer than 4” pumps, so you would not be able to get the pump intake set as low in the well with a 3” compared to a 4”. When your well is 130’ deep and the pumping level is 126’, the deeper setting of the pump intake is important.
    some good insight . thanks
    im aware of longevity issues relating to rpm speed from operating gen sets and higher rpm never last as long as lower running ones do. Probably is the same for pumps. i noticed they do sell a flow sleeve for the grundfos 3 inch pumps. dont know why though.
    the 4 inch goulds pumps seem to have Centripro motor not Franklin motors unless franklin makes centripro motors also. i dont see any grunfos 4 inch pumps only 3 inch.
    when talking about what depth to set the pump at do people refer to that number in referance to where the intake of the pump is set at or in referance to the top or bottom of the pump?
    If putting a 4inch pump in a 4.5 inch casing does it matter that there is only .25 of an inch or so around the pump once in the hole. i read that most 4 inch pumps wont fit into a 4 inch casing although this is a 4.5 inch casing ( or at least thats what the reciept says, ill have to make sure by actually measuring it)

    Looking at the diggers reciept i noticed that he dug to 140 ft total but set perferated pipe from 130 to 110 ft. so when you commented that as long as the pump isnt set below the perferated pipe it should be ok if the pump is set at 126ft since that is still 4 ft above the perferated pipe end.
    thanks for all the input from everyone.

  3. #18
    DIYer, not in the trades LLigetfa's Avatar
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    Quote Originally Posted by valveman View Post
    The 3” pumps are also a little longer than 4” pumps, so you would not be able to get the pump intake set as low in the well with a 3” compared to a 4”. When your well is 130’ deep and the pumping level is 126’, the deeper setting of the pump intake is important.
    If using a sleeve that is completely sealed at the top, it effectively lowers the intake to the bottom of the sleeve.

  4. #19
    DIY Senior Member craigpump's Avatar
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    Franklin does not make Centripro motors.

    Grundfos does make a 4" pump, but their motors are questionable.

    Actually, a 4" pump is 37/8" in diameter so it will fit perfectly in 4" ID PVC.

  5. #20
    DIY Senior Member VAWellDriller's Avatar
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    If a Grundfos 3"pump is set totally top feeding situation, it will overheat and shut itself off....I've personally seen it happen, and putting a piece of 3" DWV pipe cured it instantly. As far as the high speed of the Grundfos, yes it's fast, but they seem to have designed every part to work that way; I've put in scores of them oldest being about 7 or 8 years, and never had even 1 fail for any reason at all. It's not my pump of choice because of cost and limited selection, but in situations like this where you cannot install a sleeve on a 4"pump, and want to set it deep in the screens where it may not get good cooling flow;its a good choice. If the couple inches it is longer than a 4" motor are a problem with the depth setting, you've got a lot bigger problems. I have never used their variable speed controller, so I can't offer an opinion on that. As Craig said, all 4" pumps as made to fit 4" pipe....(sch 40 pipe). Any reputable driller or pump service could sell you a Grundfos pump.

  6. #21
    DIY Junior Member ndwolf's Avatar
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    thanks for the input everyone. it seems like there is no real answer to this. the choice is install a 4 inch without the sleeve and hope it cools ok or go with the higher rpm 3 inch grunfos with a sleeve and hope it will last just as long.
    what really gets me now is why the h... the well digger didnt put a larger casing in. he knew what the application was for so why wouldnt he put a larger casing in so that a 4inch pump with sleeve could be installed. Just goes to show i should have done the research and not trusted someone who had 25 yrs of drilling wells to make the decisions. ill be calling him on Monday to see what his reasoning was.

  7. #22
    DIY Senior Member craigpump's Avatar
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    I have a couple dozen CU 301 controllers out there and have had no issues with any of them.

    One advantage the SQE offers is that if the controller should ever fail, a regular pressure switch can be installed and the system will operate just like a regular "dumb pump".

  8. #23
    DIY Junior Member ndwolf's Avatar
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    Quote Originally Posted by craigpump View Post
    I have a couple dozen CU 301 controllers out there and have had no issues with any of them.

    One advantage the SQE offers is that if the controller should ever fail, a regular pressure switch can be installed and the system will operate just like a regular "dumb pump".
    is the cu301 controller what varies the speed to the motor. if so why do the variable speed stuff get such bad reviews

  9. #24
    DIY Senior Member craigpump's Avatar
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    The CU 301 works in conjunction with the electronics in the pump motor to control the pump speed.

    There's a whole host of reasons VFD's get a bad name, they weren't very reliable when they first hit the market, there were reports of radio interference, they aren't any less expensive, the control units are very expensive and prone to damage due to lightning......... I prefer a standard dumb pump, pressure switch and a large tank.

  10. #25
    Moderator valveman's Avatar
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    Quote Originally Posted by craigpump View Post
    There's a whole host of reasons VFD's get a bad name.
    Engineer quote from 1968
    “I predict the recent introduction of Variable Frequency controllers will make constant speed motors a thing of the past”.

    Engineer quote from 1982
    “Variable Frequency technology will revolutionize the pump industry in less than a decade”.

    Engineer Quote from 1993 (the same year Cycle Stop Valves were introduced)
    “The rapid advancement of Variable Frequency Drives will render the pump control valve obsolete within a couple of years.”

    Engineer Quote from 2013
    “Someday I'll wrap my mind around CSV and reach a conclusion, but with VFDs getting better and cheaper by the day the issue may become sidelined soon.”

    No matter how bad they want it to be true, the laws of physics have been a formidable stumbling block for VFD’s. For over 40 years VFD manufacturers have been beaten back by the side effects of varying the pump speed. VFD’s cause many problems including resonance frequency vibration, voltage spikes, harmonics, EDM currents, parasitic losses, cooling issues, and many others. Had Mother Nature not gotten in the way with these issues, VFD’s would have taken over the industry many years ago.

    However, because of the tremendous profits from VFD sales, along with being able to con people into falsely believing VFD’s save energy, the VFD ruse continues to this day. VFD’s HAVE become better and cheaper, but they will never be able to overcome obstacles created by the Laws of Physics.

    The Cycle Stop Valve was invented to replace VFD’s over 20 years ago. In contrast to the continuing problems and associated “updates” to VFD’s, the CSV works WITH the Laws of Physics and therefore has changed very little in 20+ years. We have learned that the more VFD’s sold, the more there are to be replaced with CSV’s later.

    I have been hearing that VFD’s are getting better and cheaper for so long, you would think people would realize by now that you can’t fool Mother Nature. But then again even though the evidence is overwhelming against it, many people still believe in man made global warming and that our government is here to help us.

  11. #26
    DIY Junior Member ndwolf's Avatar
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    does anyone know if they make a 4 inch pump that has overheat protection or is there a control unit that can detect overheat and shut the pump down?

  12. #27
    Moderator valveman's Avatar
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    Quote Originally Posted by ndwolf View Post
    does anyone know if they make a 4 inch pump that has overheat protection or is there a control unit that can detect overheat and shut the pump down?
    All submersible motors have thermal overloads built into them. The problem is that by the time the motor is hot enough to trip a thermal overload, it is already hot enough to cause damage. It is best to PREVENT motor heating instead of trying to shut the motor down after it has overheated. A Cycle Sensor to prevent running dry, and a flow inducer to make the flow go past the motor is an ounce of prevention that is better than a pound of cure.

    Quote Originally Posted by VAWellDriller View Post
    If a Grundfos 3"pump is set totally top feeding situation, it will overheat and shut itself off....I've personally seen it happen, and putting a piece of 3" DWV pipe cured it instantly.
    Good to know VA. I don’t think it is supposed to happen like that, but I am not positive the SQ has the little internal pump. I think that was in the “jetsub” which was the precursor to the SQ pump. I am not positive they incorporated the internal pump into the SQ.

  13. #28
    DIY Junior Member ndwolf's Avatar
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    Quote Originally Posted by valveman View Post
    All submersible motors have thermal overloads built into them. The problem is that by the time the motor is hot enough to trip a thermal overload, it is already hot enough to cause damage. It is best to PREVENT motor heating instead of trying to shut the motor down after it has overheated. A Cycle Sensor to prevent running dry, and a flow inducer to make the flow go past the motor is an ounce of prevention that is better than a pound of cure.



    Good to know VA. I don’t think it is supposed to happen like that, but I am not positive the SQ has the little internal pump. I think that was in the “jetsub” which was the precursor to the SQ pump. I am not positive they incorporated the internal pump into the SQ.

    i agree but if i used a 4 inch pump the flow sleeve is not possible so i thought maybe there was some other protection possible.
    can anyone explain how to put a piece of 3" DWV over a grundfos 3 inch pump. i understand how its suppose to work by causing the flow to go around the motor before going into the pump intake but not sure how the DWV would be fastened to the pump and how or if it has to be sealed around the top where the drop down pipe meets the pump.

  14. #29
    Moderator valveman's Avatar
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    Cut three pie shaped wedges from the top. Slip it over the motor and pump until the pie shaped cutouts are a few inches above the pump intake and the bottom of the flow inducer is even with the bottom of the motor. Use a 3” hose clamp to draw in the pie shaped wedges to tighten against the pump. Then use electric tape to cover over the hose clamp and the gaps between the cutouts.

    Here is a video if a similar one on a much larger pump.

    http://www.youtube.com/watch?v=sVBpCVqX7Jk

  15. #30
    DIY Junior Member ndwolf's Avatar
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    Quote Originally Posted by valveman View Post
    Cut three pie shaped wedges from the top. Slip it over the motor and pump until the pie shaped cutouts are a few inches above the pump intake and the bottom of the flow inducer is even with the bottom of the motor. Use a 3” hose clamp to draw in the pie shaped wedges to tighten against the pump. Then use electric tape to cover over the hose clamp and the gaps between the cutouts.

    Here is a video if a similar one on a much larger pump.


    http://www.youtube.com/watch?v=sVBpCVqX7Jk
    thanks that helped. one other question i have is do you secure the safety cable for the pump along the drop down pipe every so many ft or does the safety cable stay free from the drop down pipe. also i read that 1 1/4" pvc poly stretchs over time. do you have to allow for this in setting the pump depth (and if so how much)or is it to little stretch over the 120 ft distance to worry about.

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