Steven;
The diaphragm pumps have a pressure switch to turn the pump on and off.
I assume that is the part with the 2 wires. One goes to the switch and the other goes to the pump motor.
If you hook it up properly, it should shut off the pump when the pressure switch reaches the set pressure.
If it does not, either the switch is not working or the pump is not building up to the required pressure.
Larry Cobb
Mikey Board Supporting Member