*PLUMBERSSTOCK EXPERT* responded:
Howdy! We appreciate your inquiry about our Square D FSG2J21M4 30/50 Pressure Switch with a Lever. The lever has auto and off positions. It is a disconnecting switch as well as a manual cut-out lever if the pressure drops below a certain point. If there is a break in the water line as it comes from the well to the pressure tank, the tank will lose all its pressure. The pressure regulator and the lever will shut off the power to the well pump due to pressure loss, otherwise, the pump will keep on trying to pressurize the tank with no success because of the break in the line going to the tank. But, you must briefly hold the lever down when putting water back into the tank without pressure (long enough for it to pressurize). We hope this helps. If you want to purchase this Square D FSG2J21M4, feel free to hit the "Add to Cart" button, enter your postal code and you'll be all set. Thank you for visiting PlumbersStock.com. Have a wonderful day!