Pressure Tank Size

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by jed1154, Jan 22, 2020.

  1. jed1154

    jed1154 Member

    Joined:
    Feb 11, 2008
    Location:
    Texas
    TLDR: I have a 5HP well that pumps 50GPM and I need to install multiple pressure tanks to keep from burning it up so it can serve my residence. How many and what size do I need?

    FULL VERSION:

    I am moving into the family ranch home. We have a well but it is currently piped to a stock tank. The home already has plumbing set up for the well to serve the house, however, the original pump was replaced with a giant one for stock tank topping off.

    So...I have a 5HP pump that is putting out 50GPM. Currently, it free flows to the stock tank when turned on. My local well guy says that often in these situations, people install 'ring tanks'. Basically the well fills the ring tank which then fills a small pressure tank and the house. However, the cost of this is prohibitive. It was suggested that we could also install MULTIPLE pressure tanks to satisfy the 2 minute run time suggestion so that the pump doesn't burn up. I did look at CSV and spoke to the owner, but this is not a solution here as the flow requirement to activate that is well over what would be used in a shower.

    So...I have room for multiple pressure tanks and a softener, but I don't know exactly how many tanks and of what size I need to keep this pump from cycling too much. Can someone help out with that? This solution would be very cost effective as I can do the install my self.
     
  2. Reach4

    Reach4 Well-Known Member

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    Location:
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    Do you know the GPM rating on your pump that puts out 50 gpm?
    Simplistic answer: 50*4=200. Go with two 119 gallon WX-350 pressure tanks.

    Why did you want 50 gpm? I think the answer was that you stood there while the tank was getting filled, and you did not want to stand there longer.

    A pump sized to fill a stock tank should not be expected to have to produce much pressure other than what it takes to raise the water. However that pump could produce more pressure at 7 to 10 gpm, as used for a house. So maybe branching to the stock tank and the house could work, if you could put up with a pressure drop while filling the stock tank. For that, you would want to characterize the pump better. You could measure the deadhead pressure by running the pump output to just a pressure gauge for 30 seconds. It may be that you could use a CSV on the supply to the house, but go with one that has a higher minimum flow.

    If you were to replace the pump at some point, you could go to an auto-fill on the stock tank, and use a smaller pump.
     
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  4. valveman

    valveman Cary Austin Staff Member

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    You can't put enough tanks on a 5HP, 50 GPM pump to keep it from cycling too much, especially when filling stock water with float valves or irrigating with varied rates. This is a perfect application for a CSV. With a CSV you can use any amount of water you want, that is kind of the point fo a CSV. Without a CSV, every pump company is going to recommend you irrigate and fill troughs at 50 GPM all the time, to keep the pump from cycling too much. I have seen systems like this with a half dozen 86 gallon size tanks and it still cycled too much.

    There are two different CSV's that will work with that size pump. The CSV125-3 and the CSV3B2T. Using the CSV3B2T as an example, it will have a minimum flow of 5 GPM. This is plenty to keep the pump cool, and is also the rate that will fill the pressure tank. The 86 gallon size tank holds 20 gallons of water. With a 40/60 pressure switch, the CSV3B2T is set to 55 PSI constant. In this way it will only fill the last 5 gallons of the tank at 5 GPM, which will give you one minute of run time, on top of the time the pump has already ran to supply whatever water you were using. So even when taking a 3 GPM shower. The CSV makes the pump act like a 5 GPM pump instead of a 50 GPM pump. In this way a 3 GPM shower would use water from the tank for 7 minutes, then the pump would run for about 2 minutes to refill the tank. A 10 minute shower would only cause one pump cycle. The main advantage of the CSV is that when using more than 5 GPM, there are absolutely no cycles on the pump. No matter if you are using 6 GPM, 16 GPM, 26 GPM, or 46 GPM, the CSV will hold the pressure at a constant 55 PSI and not let the pump cycle even once.

    Using two of the 119 gallon tanks or even four of the 86 gallon tanks the pump will still cycle all the time unless you are using 50+ GPM. Not to mention the more tanks you have, the longer your house will be at low pressure. With a 40/60 switch the pressure will hover above 40 PSI for a long time before the pump starts and you start seeing some good pressure as it gets closer to 60 PSI. Then the pump shuts off and you start seeing decreasing pressure all over again. 55 PSI constant will be much strong shower pressure than when continually cycling between 40 and 60. This is especially true when using a 5 GPM shower head, so the pump doesn't cycle even when a shower is running.

    The CSV125-3 will actually work down to as little as 3 GPM, which gives you constant pressure as long as you have at least a 3 GPM shower head.

    Also, no matter if you use a CSV or just a bunch of expensive and short lived tanks, the float valves in the troughs need to be non-modulating float valves, not modulating type like in a toilet. Modulating float valves allow very little flow as the tank is almost full, which can cause cycling for hours to put the last 1/2" of water in the trough.

    Oh yeah, the 50 GPM, 5HP pump is one of the most common applications for the CSV3B2T or the CSV125-3. Been doing it this way since 1993. Listening to any negative comments about the CSV could keep you from using the one thing that could benefit a system like this the most.

    Here is a link to a review from a Chicken Farmer who can testify a lot of big tanks is not the answer.
    http://forum.cyclestopvalves.com/index.php?topic=2207.0
     
  5. jed1154

    jed1154 Member

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    Texas

    The stock tank is 3 acres. It does not have a float. It comes on when I decide it needs to come on and it runs until I shut it off.

    Well, we spoke about this on the phone a long time ago. And I thought the overall decision (at least from what I understood) was that this wouldn't help much as I don't have any appliances that use 5gpm. So...without a device that will even cause the valve to activate, how does this setup help my situation? The tank is still going to draw down at 1.5gpm as though there were no valve....and I am still going to have pressure fluctuations. I'm simply not willing to use a 5gpm shower head. I don't even know that you can find such a thing, and its excessively wasteful to say the least.

    What am I missing? I like your device. A lot. I just have to make sure I understand that it will be of benefit here. How can it help me if I don't have anything using 5gpm? Also, the stock tank can be removed from this equation as it is piped directly to the stock tank. It bypasses the CSV completely. The CSV would only be used to serve the house on the same well.



    To fill the stock tank at a reasonable rate during droughts. This is a 3 acre tank. When we turn the pump on, it runs for days or even a week. We don't wait for anything. We turn it on one day, and turn it off a week later.
     
  6. Reach4

    Reach4 Well-Known Member

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    Location:
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    Supports a 3 acre feed lot full of cattle, or the "tank" is really a big pond?
    Right now there is no pressure switch or pressure tank. You turn on a switch, and not a valve.

    Anyway, I would try the deadhead pressure test. The 30 seconds is more than enough time to read the pressure, and too little time to overheat the pump.

    I am thinking of maybe a house pressure switch controlling a valve that limits the flow to to the 3 acre tank when the house wants water. Maybe a check valve on the input to the pressure tanks and pressure switch?
     
  7. jed1154

    jed1154 Member

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    Yes...stock tank...pond.

    Anyway, I'm just interested in figuring out how to tie the well back into the house. All of the equipment is here for that, as that's how it used to be functioning (with a 1hp well pump and not a 5hp, LOL). I'm not worrying about how to supply the stock tank, it's rarely used. Forget that part of the equation. Just how to make a 5HP 50GPM pump work with an existing pressure tank already plumbed to the house. Maybe that's the CSV, maybe it's 4 big tanks...that's what I'm here to determine and understand.
     
    Last edited: Jan 22, 2020
  8. valveman

    valveman Cary Austin Staff Member

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    Pump Controls Technician
    Location:
    Lubbock, Texas
    With such a large stock tank or earth pond it is good that you have the pump running wide open and don't have to worry about the pump cycling. You don't need a CSV, pressure tank, pressure switch, or anything to control a pump that is just running wide open filling a pond. But there are still many reasons a $700 CSV and a $500 pressure tank will do a much better job than a couple of $1000 pressure tanks. Especially because you never use more than 5 GPM in the house, it is best that the CSV makes the pump work like a 5 GPM pump rather than the 50 GPM pump that it is. Starting and stopping a pump at 50 GPM causes water hammer and high inrush currents for long periods of time, check valve failure, etc. With the CSV3B2T the pump will start and stop at 5 GPM, completely eliminating water hammer along with check valve and other component failures at the same time.

    A house only uses about 300 gallons per day. Because of the slower tank fill rate of the CSV, using an 86 gallon tank that has 20 gallons of draw will cause the pump to cycle about 10 times per day. Using two of the 119 gallon size tanks having 30 gallons of draw each and without a CSV the pump will still cycle 10 times per day. The little extra run time the CSV causes to make this happen is a good thing. Short run times, short off times, and starting/stopping the pump at maximum flow as when not using a CSV is much harder on the pump.

    Oh and BTW a 50 GPM, 5HP can build 168 PSI, which you can deduct 1 PSI for every 2.31 feet down to the water level. I know it is counter intuitive but, it is much easier for that pump to start and stop with 167 PSI against it like when using a CSV, as it is to let it start wide open at 50 GPM.
     
  9. jed1154

    jed1154 Member

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    im just terrified of using the device given the mixed reviews and IM having to clear this with the guy that had this equipment installed. If this pump fails after installation, I’ll not only be paying all labor and materials costs but I’ll have to listen to complaints of how I killed the pump .... indefinitely. The guy that installed the equipment has several trusted drillers and installers and none of them agreed to install it or suggest installing it which makes this an uphill fight for me.

    That said, the main push back I get is that we are basically choking down the flow and that will put undue stress and burden on the pump. It’s like slowly approaching a dead head. If dead heading is bad, surely choking it down is as well.

    How do you respond to this concern? Obviously, I'd rather install a single device like this, in line, to equipment that is already ready to rock and roll than spend a bunch of money on tanks and then have to install those as well.
     
    Last edited: Jan 23, 2020
  10. valveman

    valveman Cary Austin Staff Member

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    LOL! I feel ya! I have been getting push back since I filed for five patents on the idea in 1993. That's right! TWENTY SEVER YEARS AGO, AND FIVE PATENTS! And in 27 years there has never been a single pump damaged by a CSV. On the contrary, CSV's have made hundreds of thousands of pumps last longer than they did previously. Many of those first test cases I installed almost 30 years ago are still running today, when they were lasting an average of 7 years prior to installing a CSV. Most of the first cases that tried CSV's had nothing to lose, as they had already tried larger tanks, VFD's, and many other things and still couldn't make the pumps last. The CSV's made test cases that preciously lasted only a year or two last more than 12 years. Other systems where the pumps would only last maybe 3 to 5 years, adding a CSV made them last 20+ years so far. The CSV more than doubles the life of the pump, and many have lasted 600% longer so far. And if you don't think the US Patent Attorneys went over back pressure and motor cooling with a fine-tooth comb, think again. But it did take 6 years for even the smartest engineers in the US Patent office to research and figure out it would work just as I said and issue the patents.

    I fully understand why pump guys think that way. I thought exactly the same way for the first 20 years of the 50 I have been working with pumps. The words "chocking" and "throttling", which is what the CSV does, are negative words to start with. "Deadhead" and "back pressure" are considered negative words to any pump man. But the way a CSV works is one of the only true counter intuitive things I can name. "Chocking, throttling, or increasing back pressure" on a piston or gear type pump would be a bad thing. But the centrifugal impeller, which is what all pumps in this industry are made with, has a couple of characteristics that are just the opposite of a piston/gear pump and just the opposite of what our brains tell us is correct.

    Increasing back pressure on a pump with a centrifugal impeller is good for the pump. Back pressure makes the pump draw lower amps or power and run cooler. Running a centrifugal impeller with too low a back pressure is the hardest thing for a pump. Low pressure means high flow, high amps, high motor heat, and possible cavitation. Any pump man knows when a pump is drawing too many amps and tripping the breaker, restricting the flow a little with a gate valve, ball valve, or Dole valve will reduce the amp draw, make the motor run cooler, and stop tripping the overload. I don't know why it is so hard for us to understand that continuing to restrict the flow further would make the motor draw even fewer amps and run even cooler. The only way back pressure will hurt the pump is if you close a valve all the way and "deadhead" the pump. Even then it is not the closed valve or the high back pressure it creates that hurts the pump, it is the fact that zero water is moving. With complete deadhead and zero water moving the water in the pumps gets hot quickly and the pump will not last long.

    However, deadhead has absolutely nothing to do with a CSV. The CSV can never completely close. The CSV can never deadhead a pump. The minimum flow through the CSV has been carefully researched to be about 3 to 5 times more than it really takes to keep a pump cool. You will never get a pump or motor hot with a CSV. It is just the opposite of what some people think, the motor is drawing lower amps and running cooler because of the back pressure from the CSV.

    All those pump guys will be much better pump guys when they figure this out. But I understand the counter intuitive part is hard to comprehend. It took me a couple of weeks explaining and showing for some of the engineers at some of the big pump manufacturers to understand how it worked back in 93-94. Their mouths dropped open and the light went on over their heads when they finally understood. But did they take this new product and use it to make all their pumps last 30-40 years instead of the average 7 years? Heck no! They Blacklisted it. The CEO of the pump company said "this company makes a living selling pumps and tanks. CSV's will make pumps last much longer and use smaller tanks. Anyone working for this company and mentions a CSV will be fired immediately." Took me another four years to find this out.

    Since then the pump companies have been on a rumor campaign to make people fearful of CSV's. Back pressure, deadhead, cavitaiton, and many other things are said out loud to start the rumors. But there is nothing in their warranty or nothing written to back this up. They know any engineer worth his salt or I can easily prove them wrong and that a CSV can never damage a pump. They know they cannot write anything negative about the CSV or dis-allow warranty for using a CSV, or there would be liable issues because it is not true.

    You can get by with a bunch of expensive and troublesome big tanks, but the CSV is a superior way to control a pump and any good pump man knows it. The best way to determine if a pump man knows what he is talking about is the back-pressure thing. If he thinks back pressure makes a pump work harder, he really doesn't have a clue how pumps work. Unfortunately, and maybe because of the rumors the pump manufacturers started, I would say maybe only 5% of all pump men understand this. Also, unfortunately, people keep having to buy new pumps every seven years on average, mostly because they believe the pump men who fell for the CSV rumors.

    It is a double-edged sword for me. The rumors make it hard to get people to believe the truth about how a CSV works. But if it weren't for the rumors every pump owner would be demanding a CSV. Every pump company would be selling a version of the CSV, all pumps would last 30+ years, and I would be out of business myself. Planned obsolescence cost consumers millions of dollars they should not have to spend. Planned obsolescence is good for pump companies as well as my business. If every pump had a CSV, nine out of ten pump companies as well as me would be out of business. I am just amazed at how many people keep falling for the rumors. :)
     
    Last edited: Jan 23, 2020
  11. valveman

    valveman Cary Austin Staff Member

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    Here is a prime example. This pump is using an old Hydro Servant valve, that was very similar to the CSV. However, the Hydro Servant did not have the patented non-closing feature of the CSV. The Hydro Servant worked at much lower minimum flow, and could deadhead the pump if not set correctly. Even so, this pump lasted 53 years using a valve similar to the CSV. Both the Hydro Servant and the Aqua Genie valves were discontinued a long time ago by the pump companies who made them. They were not discontinued because they made pumps fail prematurely, but just the opposite. Red Jacket pump company who made the Hydro Servant and Franklin pump company, who made the Aqua Genie stopped making them BECAUSE they made pump last too long. The patented non-closing feature of the CSV solved the only problem with those previous valves and will make pumps last even longer still. That is why the pump companies are mad and will say anything to keep you from trying a CSV.

    See the thread here;
    https://terrylove.com/forums/index....anyone-know-what-kind-of-valve-this-is.83778/

    53 year old pump.jpg

    hydroservant-1.jpg
     
  12. jed1154

    jed1154 Member

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    Feb 11, 2008
    Location:
    Texas
    I have two cab options available to me. How do I decide between them?

    and just so We are clear, if I don’t use 5gpm, then this device will NOT keep my pump from cycling any better than if it were not installed, but it WILL slow the flow so that the run times are longer, correct?
     
  13. valveman

    valveman Cary Austin Staff Member

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    Pump Controls Technician
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    I'm sorry. I know you are overwhelmed with information. But you are getting a valuable education. Choose the right one and you will have stronger pressure and never have to think about your water system again in your lifetime. Choose the wrong one and you will be replacing pressure tanks regularly and your pumps will last an average of seven years. It is a complicated subject. Even the half dozen pump guys you are talking to don' t understand how pumps work, and they do this for a living. But again they sell pumps and tanks for a living? Are they really thinking about what will last the longest and cost you the least?

    And no we are not clear. When you are using water in the house at less than 5 GPM, it is much better to have a 5 GPM pump doing the job than a 50 GPM pump banging on and off continually. The CSV3B2T will make the pump work like a 5 GPM pump when the house is using water. But when you need 6 to 50 GPM the CSV will also open up and make the pump work like a larger and correctly sized pump for whatever job you are doing.

    How about this? Use the CSV3B2T Cycle Stop Valve with an 86 gallon size tank. If you don't like how it works and/or the pump doesn't last through its warranty period because of something caused by the CSV, I will buy you a new pump, refund your money for the CSV, and you can then spend a few thousand dollars extra on a couple more big tanks? The CSV uses the same pressure switch/pressure tank system. All you have to do is remove the CSV and add another tank or two if you don't like the CSV. In 27 years only one person in the world has ever removed a CSV. And that was one of those engineers who thinks he knows everything there is to know, and was just trying to show the CSV didn't work to prove how smart he is. LOL!

    I have offered to replace any pump that was damaged by a CSV for 27 years. It has never happened and it never will. No brag, just fact. And I don't care how you use the water, a little or a lot. Tell one of those pump guys you want to run your 50 GPM pump at 25 GPM twenty four hours a day, and see if they will still warranty your pump? Then they might tell you the truth about how bad cycling is, and that it won't make it through the warranty cycling like that. But I would have no problem warranting your pump if needed. Even if it ran 25 GPM twenty four hours a day using a CSV it would not cycle itself to death like it would with just tanks.

    I am not spending all this time trying to sell you one little Cycle Stop Valve. I am explaining all this so those half dozen pump guys who are giving you bad information will get mad enough to check into what I am saying. I love to see the light bulb light up over an old pump mans head when he finally realizes how pumps work. Like me, they may have been working on pump 20-40 years. So when they figure this out it is a real eye opener and life changer. It is a shame that less than 5% will ever understand how pumps really work, so choose your pump contractor wisely.
     
  14. jed1154

    jed1154 Member

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    Yeah, I'm lost. Sorry. I just can't get my head around this. This stuff is right up my alley in terms of science and physics. I need to understand, because this will save me money and I'm willing to stay with you as long as you have the stamina to deal with me. Fear is born of ignorance and I am definitely ignorant of what exactly is going on.

    Let's start completely over. First, why did you suggest the expensive valve over the much cheaper one (CSV125-3)? Both are suitable for this size pump?

    Second...let's start with this. Let's remove the pond completely. Here is what I have:

    Air over water tank at 119 Gallons with whatever sized pipe running into that from the well. It has a 40/60 pressure gauge.

    Now...let's put the CSV3B2T in the system somewhere....and turn on the shower at 1.5GPM.

    Pressure drops to 40, pump comes on....CSV throttles pump to 5GPM and fills the tank...it goes back to 60psi...pressure switch shuts off pump....and we do this over and over again. <--Is this not correct?
     
    Last edited: Jan 24, 2020
  15. Reach4

    Reach4 Well-Known Member

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    We were think precharged tanks with the air separated from the water by a diaphragm. At least that is what I was thinking.
     
  16. jed1154

    jed1154 Member

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    it doesn’t matter. It appears as though my research and attempt at solving the problem will be for naught. The ones in charge have opted for keeping the single air over water tank and adding a precharged 119 g tank because they talked to some feller that did the same thing and it worked fine.

    Not sure if this is workable but looks like my freakin hard science degrees and Masters with engineering math is no match for the “way we’ve always done it”.

    Still like to get my questions answered in case I have a chance to teach and change their mind.
     
    Last edited: Jan 24, 2020
  17. Reach4

    Reach4 Well-Known Member

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    When you use such a tank, you normally need a way to add air, and an air release valve (air volume control=AVC) on the tank. Air gets absorbed in the water, and must be replaced. The That contact with the air in that tank can have some water treatment effect, such as removing H2S ("sulfur"). The AVC lets you not have to balance adding air carefully, and instead releases the excess.
     
  18. valveman

    valveman Cary Austin Staff Member

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    I am always amazed that people will do what the neighbor next door says or "its always worked ok like this" instead of listening someone with several patents, 50 years experience, and hundreds of thousands of systems under their belt, and even offered to warranty the pump? But it still works out ok for me. The seeds of a CSV have been planted. Those people will never be able to listen to the pump cycle on and off without knowing that is a problem. When they feel water hammer or have to replace the tanks too early they will remember what I said. Then when they have to shell out for a new pump in s few short years they will take a closer look. Someone will probably call and figure out they can purchase a $700 CSV to work with the one good tank they have left instead of purchasing another $1000 pressure tank and give the CSV a try. All anyone who has been living with the old pressure tank type system has to do is experience how the CSV works to realize how much better it is. This has happened countless times in the last three decades. Funny thing is, at this point I never hear from those people again. When using a CSV the water just dependably comes out of the faucets when needed and nobody ever thinks about their water system again. The CSV is like breathing. You don't even realize your doing it but it is what makes everything else keep working without any problems. People with a CSV can worry about other things in life, play golf, or whatever they want to do because their water system is so dependable it is the farthest thing from their mind.

    Coming back to answer your question in a bit.
     
    Last edited: Jan 25, 2020
  19. jed1154

    jed1154 Member

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    I'm more curious how you use an Air Over Water Tanks AND a Bladder tank concurrently. The AoV tank already has air admittance devices.

    Valveman - In a few short months, this well will not only be serving my home, but will also be serving my 100x100 garden irrigation system. I will easily be able to exceed the 5gpm threshold of your CSV, and this is where I think your device would really shine.
     
  20. Reach4

    Reach4 Well-Known Member

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    The AoW tank usually has an air release device. Air admittance was typically handled by a snifter valve upstream of a check valve and usually in a housing that combined the check valve and the port for the snifter valve. Use "snifter valve" as a search term. To co-exist, I presume that the air would be released before hitting the precharged diaphragm tank.
     
    Last edited: Jan 25, 2020
  21. valveman

    valveman Cary Austin Staff Member

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    Like Reach says, unless you have sulfur or iron in the water an air over water tank just adds several more items that fail often and require regular maintenance. The bleeder orifice, control check valve, Schrader valve, and air volume control are all temperamental and maintenance problems. None of these four things are needed with a bladder/diaphragm type tank set up. Then adding a bladder style tank after an air over water tank is like cross breading a horse and a giraffe. They are two different animals and are not made to work together.

    Now for your 1.5 GPM explanation.

    With two 119 gallon size pressure tanks and no CSV you have 60 gallons of draw down. A 1.5 GPM shower can run for 40 minutes before the pump will come on. During this entire 40 minutes the shower pressure will be decreasing from 60 all the way down to 40. When the pump starts at low pressure a 50 GPM pump will start hard at about 70 GPM. Then it will put 50 GPM into the two tanks that hold 60 gallons. The pump will run for just about one minute and shut off. It shuts off while pumping 50 GPM, so the check valve slams shut from wide open, causing water hammer and check valve failure. And the one minute of run time is not enough for the heat that was created during the hard start to dissipate before the motor shuts off. This process is repeated over and over no matter how much water you are using, unless you are using the entire 50 GPM the pump can produce.

    With one 86 gallon size tank and a CSV3B2T we only have 20 gallons of water in the tank. With 1.5 GPM being used the pump will not come on for 13 minutes. When the pump is started the CSV is in the 5 GPM position. This makes for a mechanical soft start that greatly reduces the duration of the inrush current. As soon as the pump starts the CSV, which is set at 55 PSI goes wide open and lets the tank fill at 50 GPM until it gets to 55 PSI. The tank will be filled to 55 PSI in about 20 seconds and the CSV closed down to the 5 GPM position again. It would regulate 55 PSI constant and keep the pump running continuously if using more than 5 GPM. But when using only 1.5 GPM, 5 GPM is still coming through the CSV. 1.5 GPM is going to the shower and 3.5 GPM is filling the last 5 gallons of the pressure tank. This will take 1.5 minutes on top of the 20 seconds it took to get the tank filled to 55 PSI. So, you will get almost two minute of run time using the CSV, even with a much smaller tank. And during this two minutes of run time the CSV has restricted the pump to 5 GPM and the amps are reduce by 30-50%. With reduced amps the motor doesn't require as much run time to dissipate the heat created at start up, yet the CSV gives another minute anyway. This way the motor is sufficiently cooled before shutting down. Plus stopping the pump while the CSV restricts it to 5 GPM gives a mechanical soft stop. At 5 GPM the check valve is only open the thickness of a piece of paper, the check valve doesn't slam shut, and water hammer is eliminated.

    But I think 1.5 GPM flow will be much more unusual than using more than 5 GPM. When using more than 5 GPM there is no comparison between the CSV and absolutely no cycling and a system without a CSV that will be banging off and on over and over as long as any water is being used. If you want to figure worst case scenario try using 10 to 40 GPM for extended periods of time. This is more common use of a pump this size and is why the CSV is a much better option. But like I say, most people have to replace a tank or three and be out of water a couple days at a time waiting for the pump to be replaced before they start to see the benefits of a CSV.
     
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Pumps and Tanks Well Forum & Blog. Water is life. Pump cycling often and not filling pressure tank Feb 12, 2020

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