This valve is utilized in vacuum systems to allow for one vacuum blower to service multiple receivers. This valve utilizes a rubber disc that seats against the valve body in both the extended and retracted positions. When in the extended position the disk isolates the receiver from the vacuum blower. Also when in the extended position the valve provides a path for atmospheric/free air to enter the receiver allowing it to “breathe” or “draw-in” air during discharge of the receiver. When in the retracted position the path for atmospheric/free air is sealed off and provides a path for air to be drawn from the receiver into the vacuum blower. This valve is also sometimes referred to as a dump valve or three-way valve.