A system for preventing debris buildup in vacuum sensor lines includes: a manifold, including a positive air pressure source and a controller; and one or more positive air pressure lines. Each positive air pressure line is in fluid communication with the manifold and can be placed in fluid communication with a vacuum sensor line. The controller is operably connected to and selectively activates the positive air pressure source to emit a positive flow of air, which can be directed into the one or more positive air pressure lines, and then into and through the associated vacuum sensor lines to evacuate debris. In some embodiments, a positive flow of air can also be directed through one or more vacuum lines of the end effector to promote the release of a parcel engaged with the end effector and/or clear the vacuum lines of debris.