Drill hole in check valve shutter ?

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by goltec, Mar 14, 2021.

  1. goltec

    goltec New Member

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    I am about to install a 1hp submersible well pump in combination with a 100 liter pressure tank and pressure switch. Now the shop where I bought the components advised me to install a check valve before the pressure tank with a small hole drilled in the shutter. Water will be pumped slowly into the pressure tank because shutter is being forced into the closed position by the pump pressure but has a small hole in the shutter. When a water tap is opened the water from the pressure tank gets out fast because the shutter will be forced into open position by water pressure from tank. Does this make sense? and is it advice-able? and if so, why? (I am in Thailand and it is not always easy to have things explained clearly because they don't speak English)
     
  2. LLigetfa

    LLigetfa DIYer, not in the trades

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    No, as you describe it, it makes no sense. If a check valve is installed backwards so that pump pressure closes it, tank pressure on the other side of it will not go higher than the pump pressure so the valve will always be closed.

    What you probably want to describe is how a Cycle Stop Valve works. The CSV is not a check valve but rather a pressure regulating valve with a precise leaking seat engineered into it. You cannot make a check valve work like a CSV.
    https://cyclestopvalves.com/
     
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  4. goltec

    goltec New Member

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    Thank you very much for your reply. And I definitely do believe what you say.
    There is a good reason why I ask this question in this forum, because the Thais often do technical things that are not right to my opinion.
    But what I don't understand is why they do this thing with the hole in the shutter if it does not work at all.
    The technicians of this shop do big jobs with pumps all the time and they assured me to do it this way.
    Because I also doubted the system, they took me to an example which you can see in the attached photo. So I would think,,,given their years of experience and the example they showed me, there must be some good reason why they always do like this, as they say thenselves.
     

    Attached Files:

  5. LLigetfa

    LLigetfa DIYer, not in the trades

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    A picture is worth a thousand words, words that you left out. The way it is shown in the picture, the full pressure the pump is capable of making is sent to the house while only supplying a trickle to the tank. It only half emulates a CSV.

    That pump in the picture is incapable of producing much pressure. Unless your pump also is incapable of producing much pressure (doubtful), you can end up with way too much pressure and burst pipes or blow off safety valves. Depending on the depth to the water, a 1 HP submersible could produce very high pressure. For example, a Grundfos 10S10-15 1 HP pump could produce over 400 feet of head which translates to over 173 PSI.
     
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  6. goltec

    goltec New Member

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    Thank you :)
    I understand. Because the pump continues to run and it takes a long time before the pressure switch will kick in and shut off the pump due to the small hole.
    Could you advise me then how to set up the system? would leaving out the checkvalve with the hole be ok and safe?
     
  7. LLigetfa

    LLigetfa DIYer, not in the trades

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    Yes.

    If you want the features of the CSV, then purchase the genuine CSV.

    Another negative for the drilled hole hack is that if the hole plugs, the pump can melt down.
     
  8. valveman

    valveman Cary Austin Staff Member

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    Drilling a hole through a backwards check valve is just another way of making a Dole valve. If this is a low producing well the drilled check valve will work as described. A 100 liter tank only holds 22 liters of water. You may want a much larger tank if you use more than 22 liters at a time.

    Pumping the low producing well through a Dole valve or drilled check valve would be best filling a cistern storage tank. Then a booster pump drawing out of the cistern can supply the house as much water as it needs.

    LOW YIELD WELL_ CENTRIFUGAL_PK1A.jpg
     
  9. LLigetfa

    LLigetfa DIYer, not in the trades

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    My guess is that this is done not due to a low producing well since the flow from the well to the house is unrestricted. Only the tank refill is restricted, probably to reduce cycling. It is a poor man's CSV.
     
  10. goltec

    goltec New Member

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    ok , very clear. Thanks a lot for your input. for now I will just leave the checkvalve with hole out. I tried to find a CSV here in Thailand but nobody knows what I am talking about. Maybe I have to order from the USA or so.

    The clogging of the little hole with a grain of sand or so is very good possible. Yes I can see the problems.... bursted pipes, burned out pump, etc.
     
  11. goltec

    goltec New Member

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    One more question please. The pump I will use has a maximum head of 90 meters. That means that the pump can build up a pressure of at least 9 bar (psi?). right? 1 bar for every 10 meters. The pressure tank that I will use is rated for a maximum pressure of 8 bar. Of course I am using a pressure switch, but what if the pressure switch fails? should I build in a safety pressure relief valve? Or do you think the pvc pipes I use will just burst way before the pressure tank gives up? (most likely I guess). In that case, would it be wise to fit in a short piece of pvc pipe somewhere in the track towards the house that has a thinner outer shell than all the rest of the piping system to in a way force this piece to burst before anything else can burst? So this piece can be located in a "safe" zone. Would that make sense ?
     
  12. valveman

    valveman Cary Austin Staff Member

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    No. Do not count on a thin piece of PVC to save you from high pressure. Get a regular pressure relief set at about 75 PSI (7 bar). Of course the pressure relief valve will need to be after the drilled check valve. The drilled check usually goes in the main line from the pump before it tees off to the tank. Flow from the well is always restricted. Only flow from the tank is not restricted.

    It is ironic that some of the parts we use to make Cycle Stop Valves come from Thailand but you cannot get a CSV in Thailand. You maybe able to order from us here in the states, but it may cost several times more for entry custom fees. The people in the US can purchase from anywhere they like, and the countries of origin usually even subsidizes the cost to the manufacturers. To the contrary, any other country trying to purchase from the US has to pay exorbitant fees to get US products shipped in. There is no "free trade" for US manufacturers. We suffer the with the most regulations, taxes, highest labor cost, and because of customs fees and tariffs are priced out of foreign markets.
     
  13. LLigetfa

    LLigetfa DIYer, not in the trades

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    OP has reconsidered the drilled backwards check valve as pictured since it would expose house plumbing to more than 100 PSI. A PRV installed after that check valve would not help since it is after the Tee-off to the house.
     
  14. Reach4

    Reach4 Well-Known Member

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    1 bar is 14.5 psi.
     
  15. valveman

    valveman Cary Austin Staff Member

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    Looking at your picture the low head centrifugal pump will work with the drilled check valve in that position. However, the house is seeing max pump pressure while the pressure tank slowly fills. This is OK with the low head centrifugal pump, but the submersible will build a LOT of pressure on the house while the tank is filling. I would not plumb a submersible that way.
     
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  16. fitter30

    fitter30 Well-Known Member

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    That swing check off pump discharge should have the guts pulled and another check added to tap water line. Pic only shows the one. Swing checks in vertical line might hang open.
     
  17. LLigetfa

    LLigetfa DIYer, not in the trades

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    I see at least 4
    2021-03-16_15-45-01.jpg
     
  18. goltec

    goltec New Member

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    Thank you all very much for the input. I will leave the drilled checkvalve out. And put in a pressure relief valve just in case the pressure switch fails to do it's job. thanks again :)
     
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