Well pump runs too long

Discussion in 'Pumps and Tanks Well Forum & Blog' started by Templass, Aug 9, 2008.

  1. Templass

    Templass New Member

    Hi all,

    About a month ago we replaced the switch (?) on our well pump. It was a 20/40 so we adjusted to 30/50.

    The pressure seems to build okay until it hits about 48 psi. After that, it seems to run, and run, and run. We adjusted the spread to 18 lbs. (30/48) but it doesn't seem to matter.

    We checked the air pressure in the tank 9-lb. capacity), and that's set at 28 psi, correct?

    Would appreciate any and all advice given.


    Last edited: Aug 9, 2008
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    the static pressure is good, about 2# less than the turn on pressure. It sounds like the pump may not be able to make it to 50 pounds. You might want to post in the pumps forum.
  3. nhmaster

    nhmaster Master Plumber

    S. Maine
    I'm going to stir up a mess of controversy here, but this advice is based on a lot of years working on well pumps, so here goes.

    I NEVER adjust a pressure switch, for 15 bucks I get the right one. The adjustment made to bring a 20/40 to 30/50 is way outside the range and capacity of the springs.

    Your cut in pressure at the tank is good, 2lbs below switch setting.
    Your cut out pressure is god only knows where cause the pump won't shut off.

    Here's the problem though. Your pump should be able to make 50 lbs without problems so you either have a plugged pressure switch line or the jet is worn out or plugged, the impeller is worn out or plugged, and last and least likely is the separator diaghpragm in the pump has a hole in it.
  4. Bob NH

    Bob NH In the Trades

    New Hampshire
    The only difference in the switches is usually the factory setting. The manufacturer specifies the settable range.

    Look at the range settings at the link. The FSG2 has a specified cutin range of 10 to 45 psi, cutout range of 20 to 65 psi, and an adjsutable range of 15 to 30 psi.


    I would not bill a customer for a new switch that then takes 5 times as long to change out as it takes to adjust the setting.

    There is more profit in selling the product and additional service but it may not be in the best interest of the customer.
  5. Gary Slusser

    Gary Slusser That's all folks!


    And unless the contacts are truly bad, the switch is rarely the cause of the problem.
  6. nhmaster

    nhmaster Master Plumber

    S. Maine
    Yep, but I don't like messin with em and like it even less when the home owner does. Most have no clue as to which spring does what. I know they can be adjusted and I have adjusted them over the years but I try to avoid it.
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