I have a catchment tank with grundfos jet pump and pressure tank. The tank comes up to 60 psi, the pump pressure switch arcs back and forth. I have adjusted the pressure switch to no affect. I have replaced the foot valve and the pick up line.

  • Could the pressure tank be water logged? No air buffer in the tank or bladder is busted/leaking.
    – crip659
    May 8, 2023 at 21:02
  • There was 22#pressure and increased it to 38# pressure. No water on the ground.
    – Jim
    May 8, 2023 at 21:26
  • A water logged tank will not leak water. It will be filled to the top of the tank with water without the pressure buffer, air gives to it. Usually the pressure gauge will go up and down fast, instead of having the pressure slowly bleed off.
    – crip659
    May 8, 2023 at 21:53
  • with the pressure tank at 60# and the pump unplugged the bleeder screw on pressure sensor line on the top of pump doesn't show pressure when it is unscrewed
    – Jim
    May 8, 2023 at 22:36
  • I sounds like your pressure tank is water-logged. As a diagnostic, turn off the pump,open a cold water valve, if water-logged the pressure should drop very quickly. If so, you can add air to the tank with a compressor WHILE THE COLD FAUCET IS OPEN. Usually tanks have a Schrader type valve to recharge it. A few minutes of putting compressed air in the tank should drive out enough water for a decent buffer. Then close the cold water faucet and USING A GAUGE, pressurize the tank to about 25-30 . PSI If the pump starts cycling normally, you found the problem....Continued below... May 9, 2023 at 0:52

1 Answer 1


Sounds like you need to replace the pressure switch.

Depending on your detailed symptoms you may also need a new pressure tank, but when you say the pressure switch "arcs back and forth" I'm going to jump on the pressure switch until you provide better details about the possible symptoms indicting the pressure tank. You don't describe the pressure instantly dropping to 40 and then instantly back up to 60, which is what I'd expect to see with a failed tank and a good switch.

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