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    nagr's Avatar
    nagr Posts: 3, Reputation: 1
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    #1

    Apr 18, 2007, 05:31 PM
    Balancing two bladder type water pressure tanks
    Former owners installed two 85 gal pressure tanks. However, only one tank seems to be filling. The pressure switch is a 30-50 set at about 32-42. The tanks are new bladder type and are pressurized to 30 psi each. They are connect in series with the water line connecting to one end of the manifold serving the two tanks. The end tank seems to fill (not sure how much) and the tank closest to the input line doesn't seem to be filling at all. What would be the proper procedure to get these balanced? I understand that they should be completely emptied, bladder pressure set two lbs. below (or above, I can't remember now) and then fill with water. I am assuming that is what the previous people did but , if so, it's not working.
    Any suggestions?
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
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    #2

    Apr 22, 2007, 07:28 AM
    You have my apologies for the lack of attention given to your question.
    Let me explain the function of a bladder tank. Pressure and bladder tanks provide a air cushion that produces water pressure in your system so your pump doesn't kick on every time you draw a glass of water. A bladder tank has a neoprene membrane in the center. As the pump puts water into the bottom half of the bladder tank the membrane compresses the air in the top half. When the pressure reaches the cut off point in the control box the pump shuts down. However you still have between 40 to 50 pounds of pressure pushing the water out to your system. As the pressure drops in the tank when you make a draw the pump kicks on and everything starts over again.
    To check, take something metal and start rapping at the bottom of the tank and work upwards. You will hear a "clunk" in the bottom half full of water. On the upper half you should hear a "clink" because the upper half should have nothing but air in it. IF the sound doesn't change or changes close to to tank top then the bladder tank must be replaced. Your air setting on the tank should be 2 pounds UNDER the cut in point in the pressure control box. If your pressure control has a 20 PSI cut in and 40 PSI cut out the tank pressure should read 18 PSI. This should be done with the pump off and no pressure in the system.

    Your 85 gallon bladder tank has the equivalent capacity of 220 gallons in a galvanized pressure tank. I can see no advantage in installing two of them in series. As I've pointed out in the explanation of a bladder tank They don't just "fill" with water. The pressure from the pump pushes water against the nneoprene membrane until the pressure of the air on top balances with the water on the bottom. At that time the pump control's satisfied and shuts down the pump. I can't figure out why the previous owner would install two 85 gallon bladder tanks unless he thought two would be twice as good or some hot shot salesman sold him a bill of goods. I would check them both for a functioning membrane and if they both check good I would remove one from the line. Regards, Tom
    nagr's Avatar
    nagr Posts: 3, Reputation: 1
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    #3

    Apr 22, 2007, 07:12 PM
    Re: balanceing two bladder pressure tanks.
    The tanks are RMT86 Water Ace tanks. The draw down chart shows 26.7 gal. at 30-50 psi. Would that mean the pump would come on when approx. 26 gal are used? If so, that is probably the reason for the two tanks as this pump serves three residences with two sprinkler systems. That is why I am replacing the pump as there wasn't suffiecient pressure/vol when the sprinklers came on. I guess I am still looking for a reason that one tank would fill and the other doesn't. I did do your clink and clank and there is definitely a difference in sound. Also the "empty" tank can be tipped a little and is very light while the other seems heavy. The air pressure cut-in in both tanks is initially about 30 psi and both rise the same amount as the tanks fill. Could there be air trapped in the one tank? I haven't tried resetting them as I am waiting until I replace the pump.
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
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    #4

    Apr 23, 2007, 06:29 AM
    Quote Originally Posted by nagr
    The tanks are RMT86 Water Ace tanks. The draw down chart shows 26.7 gal. at 30-50 psi. Would that mean the pump would come on when approx. 26 gal are used? If so, that is probably the reason for the two tanks as this pump serves three residences with two sprinkler systems. That is why I am replacing the pump as there wasn't suffiecient pressure/vol when the sprinklers came on. I guess I am still looking for a reason that one tank would fill and the other doesn't. I did do your clink and clank and there is definetly a difference in sound. Also the "empty" tank can be tipped a little and is very light while the other seems heavy. The air pressure cut-in in both tanks is initially about 30 psi and both rise the same amount as the tanks fill. Could there be air trapped in the one tank? I haven't tried resetting them as I am waiting until I replace the pump.
    I can see the sense in having one of these suckers installed,(see image) but fail to see where two would be of any benefit. I see that there's a pressure control box on each one. Are they both connected? How about dreawing me a diagram showing me the way they are configured? And by the way this is the first time we've heard that the well supplies three residences. Any more surprises for us? The three residences, do they all come off from one manifold or is one of the bladder tanks that's in series upstream from the manifold? It would seem that the original owner was attempting to use the bladder tanks bas a storage tank for the three residences. Which isw what you should probably think about installing in place of one of the bladder tanks when you replace the pump. What size pump will the replacement be?
    BTW, you stated," I did do your clink and clank and there is definetly a difference in sound. Also the "empty" tank can be tipped a little and is very light while the other seems heavy."
    But the "empty tank" should go "clink" all the way to the top if it were truly empty. This confuses me. Please draw us a diagram of the water system and at the same time a explanation of why in the world three homes with sprinkler systems are on one pump? And will your replacement pump be a residential or a industrial one? Regards, Tom
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    nagr Posts: 3, Reputation: 1
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    #5

    Apr 24, 2007, 07:21 PM
    I guess I was trying to keep the posting as short as possible. Anyway, first of all, the two tanks are Water Ace RPT 86 which do not have the pressure switch and gauge installed, my mistake. The chart still says drawdown is 26.7 at 30-50 psi.
    This is a rural/residential development of 6 lots. The original three were built about 15 years ago on a lower level about 70 feet below the next three lots which overlook them. The original houses installed a 4500 gal storage tank and use gravity feed for their water needs (about 30-32 psi). When the upper three lots were developed in the last 5 years, a booster pump was installed for the upper three lots which are on the same level as the storage tank. When the first house was built on the upper level the booster pump was a 1 hp home pump producing about 15gpm. At 30-40psi. When the second house was built, they installed a sprinkler system and replaced the old pressure tank with 2 new Water Ace RPT 86 tanks. As our home was built and sprinkler system installed we began running into problems of volume if more than one system was on at the same time which figures if the pump only produces 15 gpm. I am replacing the pump with a Gould’s HSC 15 which will produce 30-35 gpm at 30-50 pressure setting. The sprinkler systems are all set up to use 10gpm or less on each setting. So, that is the reason for the two tanks.
    Back to the original question, if one of the two tanks isn’t filling, what is the probable cause? What would be the proper procedure to make sure that the both tanks will fill.
    guddaddy's Avatar
    guddaddy Posts: 9, Reputation: 1
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    #6

    Feb 6, 2012, 09:26 AM
    Speedball11...

    I think there is an obvious advantage to having 2 tanks, if the tanks are working correctly you should 'double' your available drawdown and have longer pump running cycles. To balance the air pressure in each tank I would run a permanent line from one air fill valeve to the other - should keep the air pressure the same at all times in both tanks. I am curently replacing my one 85 gallon tank - blown bladder after 16 years - with a 2 tank system. See attachment, I would be interested in hearing any thoughts on what I am planning.
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    guddaddy Posts: 9, Reputation: 1
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    #7

    Feb 27, 2012, 08:09 AM
    Results of my install - second pressure tank after the filter(s). My primary tank is on the right and has the digital cutout switch - set to 40/60 pounds. The pump runs for approximatly 90 seconds to fill the system and cut off the pump. As I expected, the primary tank continues to push water through the filter pack into the seconday tank and the whole system 'balances' at around 57 pounds, I expect that to drop a little as the filters get dirty. I haven't measured the drawdown yet but I am able to do a complete cycle on the cloths washing machine - wash and rinse, and run the dishwasher... I think that is close to 50 gallons.
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    Pabloesguapo's Avatar
    Pabloesguapo Posts: 1, Reputation: 1
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    #8

    May 30, 2012, 09:28 PM
    I am building a new house soon and am planning the same set up. How is it working so far?
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
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    #9

    May 31, 2012, 06:23 AM
    Why don't you PM Pabloeseguapo and ask him? Let me know his reply. Regards, Tom
    bstill1200's Avatar
    bstill1200 Posts: 1, Reputation: 1
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    #10

    Oct 20, 2012, 11:49 PM
    Part of the pressure problems you are having are due to the filter system located between the tanks. You need to move the filter system AFTER the 2nd pressure tank (meaning you should never have a filter system in between the well pump and the pressure tanks.) The filters are causing unequal pressure hence the poor function of both tanks simultaneously.

    Try moving that filter AFTER the 2nd tank and that should solve your unequal pressure issues (assuming you have checked that the pressure bladders are not compromised aka "the knock test" on the tank and verifying proper psi at the check valve).

    Also forgot to add that the pressure switch needs to be on the 2nd pressure tank also. Whenever you run pressure tanks in series the pressure switch needs to be at the last tank in the series (since you are running 2 tanks that switch needs to be on tank 2).
    Wyojohn's Avatar
    Wyojohn Posts: 1, Reputation: 1
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    #11

    May 22, 2013, 01:50 PM
    Najr Two tanks are better than one... It doubles the gallons drawn down before the pump starts and minimizes pump cycling... Your problem I believe is one tank working right and a failed bladder in the bad tank ,making it waterlogged, Two tank systems are little different to troubleshoot because the good tank makes it seem all is working OK (air charges travel together ect) there is water and a small amount of air above the bladder. The bladder is collapsed on the tank bottom with very little water in it and the upper side is near solid with water... so no water can flow in or out of the tank when the pump cycles You can TEST this by lettting the air out of the tank and water will follow as system pressure from the pump fills the badder and pushes the air and water out from above the badder. (Note: there's no water above the bladder normally) Take the valve core out of the stem and let 60 gallons escape from the air valve.Then recharge the air side (to 2 lbs. under pump start pressure) in the normal way (pump side depressurized) The system will work normally for a day or two depending on the hole in the leaking bladder. Fix would be to replace the bad tank or replace it's bladder.(Sears has replacement bladders that fit other brands also)
    Hope this helps... Wyojohn
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
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    #12

    May 22, 2013, 03:50 PM
    Hi and welcome to The Plumbing Page at AMHD.com. You're responding to a year old dead threads . Please check the date before you post. Thanks
    Great advice and bang on. Stick around, become a expert and answer those hard pump questions, Cheers Tom

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