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Thread: Larger Pressure tank or bigger pump???

  1. #1
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    Larger Pressure tank or bigger pump???

    We just bought a home and added a new master bath etc (3 1/2 bath now) and with 3 kids we run through a good bit of laundry & baths. Anyway, now that we're living here, the pressure is a bit low and can be almost like our camper if any other plumbing fixture is running.

    Curently here's what we have:
    - 120ft well drilled in 2001 with a 2" casing. According to records, water level is at 56ft
    - 1.0hp Goulds 2 stage deep well jet pump model sj10.
    - Goulds v60 (60 gal equiv I think) bladder tank feeding 1" line to house about 45ft away.
    - 3 1/2 bath house, some irrigation of flower beds & garden regularly with 3 kids and a number of house guests.
    - 30/50 Pressure switch is now set to about 42/64. Pump seems to struggle at about 70psig

    Problem:
    - decent pressure initially, but drops as soon as the tank is no longer helping.
    - pump can only hold about 40psi with one hose bid open and nothing else.
    - our last house had a 6" deep well (585ft) with a large submersible pump & 220gal galvanized tank. It could recover even with multiple sprinklers or showers and still build up enough pressure to shut off. This was a different location, and expensive, but served us ideally.

    With what I have now, I hate to go too crazy as we have really good, clean reliable water and the well is pretty new. I'm thinking that perhaps adding a large (315gal equiv) bladder tank with our 60gal equiv tank would allow 2 or more showers or God forbid a load of cloths washing simultaneously with good pressure before relying only on the pump. What do you guys think? I don't think that a CSV will do much improvement as the pump can't really develop enough working pressure and flow for us.

    I realize that a pump is (maybe a 1.5-2.0hp 3 stage) would be a better solution long term. However, right now I can't find out much about the well's production capability, and I hate to overload it. I figure that I could get a couple of years out of this pump until we start irrigating our flowerbeds (not yet built) and garden. Then I can upgrade the pump and the large tank(s) would be necessary anyway.

    Any pros/cons to the large pressure tank with the current pump setup? All advise is appreciated.
    Thanks.

  2. #2
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    House with 3 kids, 3.5 baths, house guest, flower beds, and garden irrigation, this is what I call a normal house system. You need a CSV more than anything. The question is, does the CSV need to be on the well pump, or on a booster pump from a cistern.

    A 315 gallon pressure tank only holds about 45 gallons of usable water. Even 2 or 3 of these would be a short term solution to a long term problem. Flower beds and garden irrigation is a long term water use. 3 kids and a bunch of house guest is another long term water use. Not only are they long term water uses but, they will require many different flow rates for long terms. Not only would a pressure tank not hold enough water as you will need but, would then take a long time for the pump to refill after the water is no longer being used.

    This is exactly what a CSV is made for. You can put in a big enough pump to handle any or all of the water use events at the same time. Then the CSV will vary the flow rate to match whatever you are using. All this with a very small pressure tank, like the one you probably already have. It is just a matter of, does your well make enough water to handle the peak demands for an extended period of time? If not, then you need to store water in a large cistern tank. A 1,000 gallon cistern, does hold a 1,000 gallons of usable water. Use a large enough cistern to supply peak demand for the longest period of time needed. Then use a booster pump with a CSV and a small pressure tank, to supply as little or as much as you need at any time.

    Example;
    Garden or flower irrigation uses 5 GPM for 6 hours a day. Three showers, a washing machine, and a toilet and ice maker needed all at the same time, is another 12 GPM for at least 30 minutes.
    Then you need about 2,000 gallons stored and a booster pump that will deliver at least 17 GPM at 50 PSI.

    If your well will make 17 GPM, then all you need is a bigger pump and a CSV.

    Cycle Stop Valve Website

  3. #3
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    Thanks for the info valveman. I tend to agree & have read a lot about your CSV. You hit the problem on the head though... the pump struggles a bit to keep up at any real pressure (50psi or better).

    I did adjust the pressure switch today to get the 42-62 that I mentioned and found that the pressure switch line was nearly blocked. Tonight, showers were noticably better because the pump actually kicked on reliably at 42psi rather than closer to 10-15 sometimes.

    I tend to think that the well is reliable for 17gpm. Our sediment filter was there for well over a year and other than the housing being a little green, had no sediment or anything reducing flow.

    I think that a 3 stage pump would make the about the same flow that I need, but appears that it could do it at about 50+psi vs 35-40 that this pump does. With that I would consider a csv. How hard is it to replace the pump myself? We do most things ourselves around here as there's not a lot of help around. I have a tractor & loader that might help to pull things out. I just don't need another big project right now. That's why I was thinking of a bigger tank to provide a little more storage for multiple showers. Then I could do the pump later when we are more settled in the house. Right now, I still have a lot of tile to lay, cabinets to finish & whole master bath plumbing to set!

  4. #4
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    You're making an assumption that isn't correct; a pressure tank doesn't add pressure to what the pump delivers. When a pump shuts off, the tank is at the same psi as the cut-out setting of the pump's pressure switch (the highest number). IF you have the captive air pressure set correctly, 1-2 psi less than the cut-in setting on the switch with no water in the tank, as soon as you use any water the pressure falls on its way to the cut-in setting. It doesn't matter how large the tank is, size only matters as to how long it takes for the pump to come on again (draw down gallons). Twenty gallon or 200,000 gal tank, same pressure.

    The higher the pressure you operate the pump at, the more water you use, then if the recovery rate gpm of the well is less than the gpm you're drawing, the farther down the water level in the well falls and usually the less water the pump can deliver to the fixtures. Hence the pump can't raise the pressure up to cut-off and you live with a lower average pressure.

    You need a new pump or to fix any water leak in the plumbing from it to the switch. If there is a check valve at the pressure tank, it will mask a leak before it - back to the pump.

    A new correctly sized pump for the well and volume of water used and a CSV and small pressure tank is your best choice. Lower pressure settings can help. To size a pump you need a pumping test of the well and to determine well depth etc..

    Gary
    Quality Water Associates
    www.qualitywaterassociates.com
    Softener Forum

  5. #5
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    Gary, I'm certainly not an expert & hear what your saying, but in part I disagree. A larger pressure tank it would seem, has to maintain a larger quantity of water at say 60psi since the pump goes to about 64 right now. The water pressure will be higher until all of the draw down is used and the pump kicks on at about 42. Consequently, I could have 2 showers (assuming the tank is about full) before drawing all the way down to the point that the pump kicks on. ie. higher pressure - for a while, like a shower.

    You of course are correct that it doesn't really increase the pressure in the system once the pump comes on, but neither does the csv. The csv is only as good as what the pump can produce, right? Therefore a csv on the current pump would leave me at 42psi or less i think.

    I'm not aware of any water leaks... most everything is new (except well 2001).

    Yes, if I use a higher pressure pump, I'll use more water - slightly. However, my intent is to use more water I'm not too worried about the well on any of the pumps that fit my application because the current pump will run continuously for long periods when use has been very high for irrigation, swimming pool etc with no problems except that it can't do much else.

    Thanks for your input... I'm hear to learn as we don't have much in the way of well support in my area. I agree that I need to test the well to size the pump, but can I do this myself and is it really going to matter much? With a 2" case, vertical pump there doesn't seem to be much difference in the ratings between a 1hp-2hp with regards to flow... only pressure as the larger HP units are 3 stage. It would seem that the well would have to be really marginal for one of these larger pumps to cause a problem. I'm more afraid of trying to replace it myself although we do most everything ourselves.

    Last thing, I just can't get it out of my head that a large bladder tank would improve the daily impact of the well on showers, dishwashers etc by putting more water at 64psi so that we don't immeadiately rely on the pump? Also, I can't quite get out of my mind that the CSV only 'evens out pressure' which is not my issue really. It seems as though a CSV throttles the discharge of the pump so that it holds a fixed pressure (assuming the pump can match the requirement) rather than letting the pressure come on up and trip the switch. I don't care too much if the pressure comes up higher than desired as there is no negative impact for me. If my shower cycles between 50-70psi that's fine. If it's at 30, thats not.

    How hard is it to change the pump? Goulds cut sheet refers to 2 installations for my pump. 2 pipe system and a "packer" system. Mine appears from the surface as though it may be a packer since the pump is right on the pipe and I do not see the 2 lines.

  6. #6
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    First of all your 60 gal. bladder tank does not hold 60 gal.
    You do need to know how much water your well produces to size the pump accordingly.
    As soon as you turn on the water the pressure in the system starts to fall. Your pressure tank does not hold a constant pressure. Once it reaches the cut in pressure of the switch the pump turns on and now is trying to supply water for your use and refilling the pressure tank. Then this cycle goes on and on and on. This wears out your pump and pressure tank quickly. In addition the water available will be under constant pressure changes. Less water is available to you when the tank is refilling.
    By using a CSV the pressure will stabilize and prevent the pump and bladder tank from going through their cycling. This gives you a higher constant pressure and less wear and tear on your equipment. The amount of water available is directly related to the amount the well can produce. The more water available the higher capacity pump and the more you have available to use. You could even go with a smaller pressure tank if you chose to.
    The pressure tank is there as a small resevoir but more importantly just to keep pressure in the system too allow instant water when wanted. When the pressure switch turns on is related to the pressure of the tanks water, not how much is in it.
    If your pump can pump the water, let it, that's what it is there for. Since you already can pump 64 psi the CSV can easily hold the pressure at 50#. Believe me when I tell you there is a marked difference between a constant pressure and the constantly cycling.

  7. #7
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    Thanks JeffGR. The problem is that Murphy has control. When you get in the shower, murphy is going to make sure that the pressure in the tank is down to about 45 PSI form toilets and other things being used. Then the tank will be empty by the time you have adjusted the temperature, and all the water you have is coming from the pump.

    If you could make sure the tank was full and the pump had just shut off, before you start a shower, you are thinking correctly. But, this will never be the case. Murphy and his law will make sure of it.

    You need a bigger pump. Even if you put on a pump that is to large and will pump your well dry, the CSV will make your pump match the amount of water being used. You then have to determine how much water your well will make, and just never turn on more than that amount at any one time.

    Cycle Stop Valve Website

  8. #8
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    Since all I did was 2" wells for the first ten years of being in business, I can tell you that with a pressure switch that is nearly plugged, you have a screen which is plugging also and a larger pump will not help the situation at all You should save your money for the larger well and a sub, CSV etc. or do like Valveman suggested. A larger three stage pump will actually make more pressure, but pump less water because of the different impeller sizes and do a worse job than the two stage.

    bob...

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  9. #9
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    quote:Originally posted by crash1068

    Gary, I'm certainly not an expert & hear what your saying, but in part I disagree. A larger pressure tank it would seem, has to maintain a larger quantity of water at say 60psi since the pump goes to about 64 right now. The water pressure will be higher until all of the draw down is used and the pump kicks on at about 42.
    Nope, doesn't work that way. As I and Jeff said, as soon as you open a faucet the pressure falls. It doesn't matter if you have 2 gals or 2 million gallons; the pressure falls to the cut in setting and the pump comes on.

    And the pressure plus the size (ID) and type of material (steel, copper, plastics [which are the slickest material]) of your plumbing, how many of what type fittings, the pressure loss in the system added up dictates the gpm/flow to your fixtures.

    Bob made me realize I forgot the 2" well. You need a new one and a correctly sized submersible pump, a nominal 20 gal pressure tank and a CSV.

    Gary
    Quality Water Associates
    www.qualitywaterassociates.com
    Softener Forum

  10. #10
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    Thanks all for the info. Believe it or not, I do agree in general with about everything said here. The easiest & most correct thing would certainly be a new well... and a new truck etc Just can't justify the $$ for that right now. I'm still trying to pay and finish the house. That's really why I'm looking for a short term fix. If the well needs replacing or I can afford to in a few years, then I'll go big as we did in our last house.

    I understand the point of the CSV a little better now and think that it could do some good.

    I know that the tank I have is not 60 gal... it's 60gal "equiv" I'm guessing if that. I apologize, but I just can't get past the possibility of more tank capacity helping. They are cheap. To me it's like my air compressor in my shop. Yes, a big compressor is better for sandblasting etc and it won't matter what size tank too much unless it's giant. However, for most every day stuff, the larger tank keeps more air in available for various tools. I would think that it would be the same here... a larger pump & well is of course the solution especially for irrigation etc. However, a larger tank will catch more of the dishwasher or bath tub etc (assuming murhpy didn't leave me empty most all of the time).

    I can't do a well and just have no sediment issues right now. Maybe it's plugged, but it sure does fine and so long as I'm not building my sprinkler system yet, even the house is not bad. I really think the build up in the pressure switch looked like kind of a green alge stuff. The well has nearly sat dormant for a year since it took me so long to do all of the work on the house. We poured some bleach in and started using it recently. Perhaps that had something to do with the switch? Most all of the wells in this area re in the 100-150ft range from looking on the net. I do think the newer ones are 4".

    I think trying the CSV will be my first step. I've also bumped the pressure a little more... 45/65 and things are pretty nice even with a tub on & shower. What size CSV? How/Where does this install - after the backpressure valve on the pump? What should my pressure switch be set for with the CSV?

    Thanks again. Will get the new well some day & a sprinkler system that'll look like a golf course!


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