An air flow control system for an agricultural product delivery system isprovided. The control system a sensor disposed within, along, or just before asecondary distribution manifold for measuring an air flow pressure therein andgenerating a signal in response to the air flow pressure in the secondarydistribution manifold. A controller is operatively connected to the sensor andconfigured to receive the signal and to adjust the air flow pressure to thesecondarydistribution manifold in response to the signal.
