bladder tank -whats up?

Discussion in 'Pumps and Tanks Well Forum & Blog' started by boboiatl, Jan 19, 2006.

  1. boboiatl

    boboiatl New Member

    Messages:
    2
    I have put a new bladder tank in my sons house and it does not seem to be filling with water. I took it off line and looked in the inlet for a plug or something that might be blocking it but all I see is what appears to be the bladder which I would guess to be normal.I put it back online and the tank stays empty -feels like no water at in it.Of course the pump cycles on and off like crazy . Do tanks come bad from the factory sometimes or am I missing something? thanks
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,990
    Location:
    New England
    You need to precharge the tank with the appropriate amount of air. This should be ~2 pounds LESS than the turn-on pressure of the pump control. SO if it is set to 30/50, it would be set to 28#. tO do this, you need to shut off the pump, open a valve and let the water run until it stops leave it open until you finish, then pump up the tank (or bleed off some air). SHut the valve and and turn on the pump and see what happens.
  3. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Our bladder tanks come from the north east part of the country. I assume the elevation up there is much higher than here in Florida. The tanks that say they have a precharge of 38 psi. Sometimes have a precharge of around 50. If that's the case with your tank and your switch is set at 50 or below, your tank will not take in a drop of water.


    bob...
  4. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    "Our bladder tanks come from the north east part of the country. I assume the elevation up there is much higher than here in Florida. The tanks that say they have a precharge of 38 psi. Sometimes have a precharge of around 50."

    If you charge the tank to a specified gauge pressure at high altitude, the gauge pressure when measured at lower altitude will be LESS than the original setting.

    EXAMPLE:
    At high altitude (atmospheric pressure of 12 psia), charge to 38 psig; the absolute pressure will be 50 psia.

    Measure the gauge pressure at sea level (14.7 psia); the gauge pressure will be 50 psia - 14.7 psia = 35.3 psig.

    There isn't any manufacturing place in the northeast that is higher than about 1000 ft. That will make a difference of less than 1 psi if you measure the pressure in Florida.
  5. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Alright; so explain the higher than labeled pressure.

    bob...
  6. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    "Alright; so explain the higher than labeled pressure."

    The factory quality control process is not perfect. They probably set the regulator wrong or some guy who couldn't read the instructions grabbed the wrong pressure labels.

    Maybe someone incorrectly converted kPa to psi.

    Whatever it was, it was not caused by any variations in atmospheric pressure.
  7. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    I guess you have to give it to them for being consistant!

    bob...
  8. boboiatl

    boboiatl New Member

    Messages:
    2
    thanks for replies but...

    I have done that-set the air pressure to around 2 below the cut in -but the tank does not seem to accept any water. The tank is still very light and system pressure is around 50 psi so I think the tank is not accepting water but could be wrong.I will try again your advice to make sure it is correct.Also my pressure switch only has a high cut off -low cut off is built in according to that.Is that normal or should I invest in a better switch which has both. thanks again to all who reply.
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,990
    Location:
    New England
    Maybe it would be good to tell how you set and adjusted the pressure. You must do it with the pump off and a valve open. Double-check the piping, sometimes the galvanized stuff can get messed up with rust. Same is true for the input to the pressure switch - it must be clean or it will have trouble sensing the water pressure properly.
  10. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Once the pump shuts off, how much water comes from the tank before the pump turns back on again?

    bob...
  11. Pumpman

    Pumpman Pump Sales

    Messages:
    191
    Location:
    So. Cal
    In re-reading the first post, boboiatl says he looked in the inlet and saw what he assumed to be the bladder. I don't think I've ever seen the bladder looking at the inlet elbow. Any thoughts?
    Ron
  12. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Maybe he stuck his finger in the elbow. I guess you could feel the bladder.


    bob...
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,613
    Location:
    Cave Creek, Arizona
    bladder

    The inlet should not have an elbow. When removed from the system any bladder tank with more than zero pressure will expand to fill the tank. It deforms/compresses as pressure pushes against it.
  14. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    We are referring to the elbow on the bottom of practically all bladder tanks.

    bob...
  15. Pumpman

    Pumpman Pump Sales

    Messages:
    191
    Location:
    So. Cal
    Thanks Speed.... I was pretty sure bladder tanks had an elbow on the bottom....
    If the bladder was distended bad enough to be seen from the elbow, I'm sure the tank needs to be replaced.
    Ron
  16. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    I will certainly agree with that. I really wonder if he is understanding the concept of checking the bladder pressure with the system pressure at zero?

    bob...
  17. Pumpman

    Pumpman Pump Sales

    Messages:
    191
    Location:
    So. Cal
    I don't know. Jim explained it pretty well in post #2.....that is, how to set the precharge correctly. I know I have customers that don't understand it.
    Ron
Similar Threads: bladder tank
Forum Title Date
Pumps and Tanks Well Forum & Blog Bladder tank leaking Sep 1, 2014
Pumps and Tanks Well Forum & Blog Replace pneumatic tank with bladder type tank without removing bleeder valve? Jun 26, 2014
Pumps and Tanks Well Forum & Blog Strange Tank bladder problem.. May 14, 2014
Pumps and Tanks Well Forum & Blog Convert bladder tank to hydro-pneumatic? May 13, 2014
Pumps and Tanks Well Forum & Blog Water Tank Bladder issues Mar 2, 2014

Share This Page