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Thread: Intermittent Pressure Loss

  1. #1

    Default Intermittent Pressure Loss

    I have a 600 ft deep well. I've owned the house 14 years and have no idea how old the pump is. The Square D pressure switch is only 4 years old.
    My problem:
    Every now and then, not always, the pressure goes below the switch's start setting and there is a delay until the pump kicks on. It had only been for a few seconds. This morning, I lost pressure while shaving for about 10 seconds, 20 seconds while showering and a few minutes while running water in the kitchen. It seems to be working fine now.
    The switch's pressure settings are 35/56 and the bladder has about 36 psi.

    Any ideas?


  2. #2
    DIY Senior Member thassler's Avatar
    Join Date
    Dec 2006


    I believe your tank should have 2 to 3 lbs less than your pressure switch cut-in setting. So if your cut-in is at 35 then your tank (empty of water) should have 32 to 33 lbs. 36 lbs might not be letting the pressure switch cut-in reliably.

  3. #3


    Thanks. I'll try letting some air out of the bladder and see if this helps.

  4. #4
    That's all folks! Gary Slusser's Avatar
    Join Date
    Aug 2004
    Wherever I park the motorhome.


    At the top of this forum are instructions to check and adjust your air pressure.

    With no water in the tank, you need 1-2 psi less air pressure than the turn the pump on switch setting. I.E. 35/56 would get 34 or 33 psi with no water in the tank. Tank manufacturers say 2 psi but hot air from a pump or air compressor will shrink in volume and thereby pressure when the cold water enters the tank. That will allow the 'bladder' to stretch farther than it is supposed to and that can shorten the life of a tank.

    Another cause of this problem is that the nipple the switch is plumbed on, or the tubing and its fittings and the holes they are screwed into on a jet pump, may be blocked with rust and that will cause a delay or lag in the switch seeing the pressure decrease in real time causing the pump to not come on before the tank is emptied.

    Another cause is something wrong with the pump and it is overheating and the thermal overload shutting off the pump for some reason.
    Gary Slusser Retired (= out of business)
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