Page 1 of 3 123 LastLast
Results 1 to 15 of 38

Thread: Well tank full of water and short cycling?

  1. #1
    Join Date
    Mar 2014
    Location
    Houston, TX
    Posts
    437

    Well tank full of water and short cycling?

    I had an inspector come check out the well and septic system on a place im looking to buy. He said everything looked good except the well tank was full of water and should only be about half full, thus causing the pump to short cycle. Anyone know anything about wells. He said this can be fixed by draining it down to the correct level. Something about air compresses and and water doesn't, so that's why it was short cycling and going from 30 to 50 psi in about 5 seconds. When they replaced the pump motor they must not have drained the tank down enough. Am I understanding this right? What I dont understand is why did I were money on an inspector vs just having a repair guy look at the well and septic and he could have just fixed it. I'll have to ask my realtor, but is what the inspector saying sound correct?

  2. #2
    Join Date
    Feb 2014
    Location
    Lake Gaston, Henrico, NC
    Posts
    8,973
    How old is the tank? If you have to add air, something else is probably wrong, unless someone changed the pressure switch to a different pressure. I've never had any experience but once you have problems with the tank holding pressure, the fix is to replace the tank.

    The tanks come precharged, but do have a valve to adjust the pressure. Changing the pump shouldn't matter for the tank.

    edited to add: I did this Google search, and found all sorts of information, including youtube videos: water pump pressure tank air pressure relative to system pressure

    If you have the old style of tank, I'd change it anyway.
    Last edited by Tom M King; 08-26-2020 at 9:11 PM.

  3. #3
    Join Date
    Jul 2007
    Location
    NE OH
    Posts
    2,615
    There are two main styles of well pressure tanks: The older style is just a plain tank that relies on a bubble of compressed air above the water to provide the water pressure to the house. Newer tanks have a rubber bladder that separates the water and the air. The problem with the old style is that the air in the tank gradually dissolves into the water until the tank doesn't have enough air in it to operate properly. That is the situation your inspector describes. The solution is, as he said, to drain the tank (all the way), allowing it to fill with air. Then when the pump is turned back on, the water will partially fill the tank, compressing the air above it.

    The bladder type tank solves the problem of the air dissolving into the water because they are separated by a flexible rubber membrane. That style of tank is charged with air to a pressure a couple of PSI below the cut-in pressure of the pump.

    I haven't seen a non-bladder tank in probably 40 years or more.

    The other possibility is that it is a bladder tank (easily identified by the schrader valve on the tank) and the bladder has failed, causing it to act like a non-bladder tank. It can be used that way, as long as you periodically drain the tank to maintain the air above the water.

    Pressure tanks are not a big dollar item and not much labor is involved in installing a new one.
    --I had my patience tested. I'm negative--

  4. #4
    Join Date
    Mar 2014
    Location
    Houston, TX
    Posts
    437
    The tank is only about 3 years old.

  5. #5
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    9,889
    Bladder has failed or it was never filled with air. Try filling it with compressed air to the water low pressure. This should work regardless of if the bladder is leaking or not. You can plumb in a air tank in the rafters to solve the problem just make sure it can be drained.
    If you have compressed air at the pump it is quicker to add air then to drain water and refill with air. Good idea to blow bugs and spiders off with the air as long as it is there.
    Bill D

  6. #6
    Join Date
    Feb 2003
    Location
    McKean, PA
    Posts
    15,595
    Blog Entries
    1
    Paul is correct. The older tanks had a device that worked with jet pumps to control the air level in the tank. They looked like a pressure regulator on the side of the tank.

    Newer tanks use a bladder inside that has air in it. This allowed the pump to reach and hold the pressure that the pressure switch was set to. If the air is gone the pressure doesn't stay above the low set point of the pressure switch would turn on, so the pump keeps starting and stopping because water doesn't compress.

    You can add air to the tank through the Schrader valve on top and your system will work properly for a while. Long term you would be better off replacing the tank. You could make the seller either fix it or deduct the replacement cost (including the plumber) from the selling price.

  7. #7
    Join Date
    Mar 2014
    Location
    Houston, TX
    Posts
    437
    Does air need to be added to the bladder occassionally?

  8. #8
    Join Date
    Oct 2019
    Location
    Maryland
    Posts
    337
    If you decide to replace the tank consider getting a larger one so that the pump does not have to cycle as frequently.

  9. #9
    Join Date
    Aug 2011
    Location
    N. Central Texas
    Posts
    116
    Paul has the right answer, I think. Replace the tank since they don't cost very much (a few hundred) and are easy to install. Since you don't own the house yet make it a condition for the sale. A bad tank can cause the pump to fail quicker and that's $$$$$. I had a failed tank bladder and tried to save some money by replacing the bladder. Mistake. Its not easy to replace the bladder. The old tank can be a smoker or wood stove for the shop with a little cutting and welding.

    Jim

  10. #10
    Join Date
    May 2018
    Location
    Lancaster, Ohio
    Posts
    1,346
    Quote Originally Posted by Travis Conner View Post
    Does air need to be added to the bladder occassionally?
    NO, as long as it is working ok. Pressure typically is set 2-4 lbs below turn on pressure setpoint.

  11. #11
    Join Date
    Sep 2007
    Location
    Longview WA
    Posts
    27,347
    Blog Entries
    1
    Many years ago a neighbor had this problem. We fixed it with a bicycle pump.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  12. #12
    Join Date
    Mar 2014
    Location
    Houston, TX
    Posts
    437
    Can you the bladder pressure with a tire gauge?

  13. #13
    Join Date
    Mar 2014
    Location
    Houston, TX
    Posts
    437
    The inspector made it sound like whoever installed the new motor and tank just didn't finish the job of adding the air pocket in the tank.

  14. #14
    Join Date
    Sep 2007
    Location
    Longview WA
    Posts
    27,347
    Blog Entries
    1
    Quote Originally Posted by Travis Conner View Post
    Can you the bladder pressure with a tire gauge?
    That is what we did. Just in case it was needed again it was written on the wall over my washing machine. We moved out of that house a dozen years ago.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  15. #15
    Join Date
    Mar 2016
    Location
    Elmodel, Ga.
    Posts
    798
    i had a similar problem several years ago and it turned out to be the snifter valve on the check valve. Don't know if this could be your problem, but its a cheap fix if it is. I would check to see if it has any damage or maybe dirt or other debris in it. Dirt dobbers are notorious for filling them with dirt.
    My Dad always told me "Can't Never Could".

    SWE

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •