My sister has a well with Sqare D pumptrol pressure switch. She has low pressure after running water for a moment. I tried to adjust the pressure switch and got the pressure to go higher at shutoff but it still goes way down before the pump restarts. I tightened a big nut and spring assembly down to get whrere I’m at now . what is the small one for ?
Usually the large spring is the pressure setting; the small screw is often the differential. That is, it would adjust the range of the operation to make it go on at say: 40 psig and off at 50 psig -instead of: on at 30 psig and off at 50 psig.