Abstract: Air flow control system comprising a pump having an air pressure outlet and a vacuum outlet; an air utilization device such as a desolderer; and a multi-position switch having first and second input ports respectively connected to the air pressure and vacuum outlets of the pump, the switch being positionable in a number of different positions whereby either one of the pump outlets can be selectively connected to the desolderer and the other vented to the atmosphere to prevent loading of the pump. In a neutral mode of operation, the desolderer is disconnected from the pump and both pump outlets are vented to the atmosphere to again prevent loading thereof. The switch also includes means for continuously varying the amount of air pressure applied to the desolderer.