A material handling system. The system includes a plurality of material sources for providing material to be transferred and a plurality of destination locations for receiving material from the material sources, wherein each destination location has a destination valve. The system further includes a distribution mechanism, a plurality of source conveying tubes each connecting a source location to an opening on the distribution mechanism, and a plurality of destination conveying tubes each connecting an opening on the distribution mechanism to a destination location. The system further includes a vacuum source operatively connected to each of the destination valves, a vacuum sensor disposed on each of the source conveying tubes configured to sense a change in pressure in the source conveying tube, and a programmable controller connected to each of the vacuum sensors for determining if a correct connection has been made.