You have a 30-50 pressure switch and a centrifugal pump. Most centrifugal pumps can't build enough pressure to turn off your pump. If you want an automatic on-off system you should have a jet pump. However you may try backing off the long screw in the pressure switch until the pump shuts off! What size tank do you have on the system? You will need at least a one gallon bladder tank otherwise the pump will continue to cycle!