A valve assembly for an air flow system, where the air flow system has a turbocharger unit and a venturi valve member for receiving a portion of the pressurized air from the turbocharger unit, and generating back pressure. The valve assembly includes a bypass switching valve and a bypass check valve. During a first mode of operation, the valve assembly is exposed to vacuum pressure, and the bypass check valve is exposed to the vacuum pressure such that the bypass check valve is placed in a closed position. During a second mode of operation the turbocharger unit is activated, pressurized air flows through the bypass switching valve, and places the bypass check valve in an open position, and the back pressure generated by the venturi valve member and the pressurized air from the turbocharger unit creates a pressure differential in the bypass check valve.