A safety device for a gas distribution system includes a valve body and an upper casing attached to the valve body, the upper casing housing two springs. The two springs are separated by a casting tube. The two springs are attached to a movable diaphragm that is exposed to gas system pressure. The valve body also includes a cam mounted within the valve body. A limit switch is directly connected to the cam such that the limit switch moves directly in response to movement of the diaphragm. Additionally, a reset pin extends from the valve body and interacts with the cam such that the cam may be reset from a closed position to an open position by moving the reset pin.