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Thread: rapid pressure drop

  1. #1

    Default rapid pressure drop

    Hello, I just started having this problem with my pressure. It will maintain pressure when not in use, but even turning on a faucet will cause a drop from 60 psi to 35 psi in 1 second or so. The result is that pump is always turning on and off every 2 or 3 seconds and causing a "surging" in pressure at the faucet. I have replaced the new pressure switch with a second new one, and the control box is 6 months old. The pump was replaced 2 years ago. Any thoughts on where to look next? Thank You

  2. #2
    Plumber plumber1's Avatar
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    Default pressure

    If you have a regular pressure tank, then the tank is water logged.
    Blow it out and pre charge it with at least 20 lbs. of air pressure before starting the pump.
    If you have an EX-TOLL like bladder tank, the bladder may be ruptured or the pre charge is out of wack.
    Or wait a while and get more advice from some well men.

  3. #3

    Default

    [QUOTE=plumber1]If you have a regular pressure tank, then the tank is water logged.
    Blow it out and pre charge it with at least 20 lbs. of air pressure before starting the pump.
    Thanks for the quick reply. It is a regular pressure tank. How do I go about the blow out and pre charge of tank. It is a new tank and I don't have a air valve on it. Do I need to install one and, if so where? Thank You

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
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    As I understand it, there are two types of pressure tanks; one has a bladder and the other type has an air makeup valve and is air over water. Each of them must have a way to get air into the system, but each differs in how it is done. On the bladder tank, there is a valve similar to your tire. You can check and adjust the air pressure as you would a tire. You must check this with the pump off and a valve opened to allow the pressure tank to reach equilibrium. then you can adjust the pressure, if required. This type must be filled to 1-2 pounds less than the turn-on pressure of the pump pressure switch.

    The other type, since the air is exposed to the surface of the water, will disolve all of the air. You need to turn off the pump, drain the tank so there is air in it, then you can turn things back on. As your pump fills the tank that air is trapped and becomes pressurized by the pump, and will push the water out, maintaining the pressure until it drops to where the pump turns on again. If there is no air in eithertank, then since water doesn't compress, it will quickly reach the turn-off pressure, but since there is no air cushion to provide the pressure storage (like a spring that is compressed), as soon as you open a valve, the pressure drops radically and the pump turns back on.

    If your tank doesn't have any kind of air valve on it, it doesn't sound right to me. The air-over-water types usually have an air make-up valve that will let air in, but prevent air or water from getting out. The bladder tanks, when the bladder fails, will fill up with water. If the valve is defective, over time, the pressure can drop, too. Note, on a Schrader valve, the primary seal is the cap, not the little air valve itself. My unprofessional experience.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  5. #5
    Plumber plumber1's Avatar
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    Default tank

    Close the valve to the house. Turn the ele. off. and open the drain valve at the bottom of the tank. If there is a plug on the side of the tank, remove it to let the vacuum off the tank so air can get in and allow the water to drain out.
    If you can do that, then dope the plug and reinstall it.
    Close the drain valve and restart the pump.
    If you have access to an air compressor and can make a connection to the drain valve then you should put 20 to 25 pounds of air pressure into the tank and restart the pump.

  6. #6
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    Default

    I'm wondering why anyone would install a galvanized tank instead of a bladder tank these days. Especially for a home owner knowing full well it is going to waterlog. Maybe the installer figured he would get more service calls this way.


    bob...

  7. #7

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    Down in my area it's been estimated that there are over 11,000 individual water systems, and my guess is that half of them still use galvanized tanks. I personally know of tanks that have been in use for 40+ years. I've instructed many of my customers on how to de-waterlog their galvanized tanks (there goes those service calls) and many of my elderly customers ask me to come by once in a while and do it for them (and have a cup of joe and a piece of pie). If I have a customer that needs a new tank, I present them with both options: a new diaphragm tank, or a galvanized tank. I do tell them that the new galv. tanks aren't as good as the old galv. tanks (at least in my opinion), and that the new diaphragm tanks are much better than the old bladder tanks. Still....it's their money and their call. I believe in customer service. If they want a new galv. tank, they get a new galv. tank.
    Ron

  8. #8
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    The difference between you and the guys I was describing Ron was you gave them not only a choice but an education as well.

    Most people never get any info on their water system, just the bill when it's finished.

    That is the reason for so many unnecessary service calls.

    I agree that the galvanized tanks airn't what they used to be. I think they are adding rust to the metal when they make them.

    bob...

  9. #9
    Plumber plumber1's Avatar
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    Default tanks

    Pumpman Bob, your my king of guy and you said every thing I was thinking.
    I'm not much of a pump person but doing service, I got into a lot of homes and I've sure replaced a ton of pressure tanks and I echo all that you said.
    And being kind to people who trust you must give you much satisfaction.
    I'm sure that the way you operate also brings you a lot more business too.

  10. #10
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    Thanks plumber1,

    And from listening to Ron's postings, I am quite sure he does the same. It is rewarding, but sometimes dishartning when the bad guy gets the job and you know his work is going to be at least somewhat shabby.

    bob...

  11. #11

    Thumbs up Thanks for all the help

    All is well now. Thanks for all the information, I learned a lot.

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