These drains incorporate a solenoid valve and an electric timer. The timer usually has two settings: time between valve openings (usually in minutes) and amount of time the valve stays open (usually in seconds). The drain comes with an electrical cord that can be plugged into a wall outlet. By matching these two settings to the amount of condensate a system produces the condensate can be removed from the compressed air system. The goal is to set the timer long enough to empty all of the condensate but not so long that compressed air is wasted. A combination isolation valve and strainer, if not standard, is highly recommended. This keeps objects from plugging the orifice inside the automatic drain valve, which will keep condensate from being released
