Waterman WRE-A Series Automatic Filters feature two stages of filtration, a coarse pre-filter and a stainless steel fine screen. The unwanted solids accumulate on the inner surface of the fine screen, building up a filter cake, which filters out even finer particles, cre­ating a pressure differential. Once the pressure drop reaches a preset level, a rinse cycle is activated by the factory supplied control system.  The solids are removed from the fine screen using a spot backwashing method, which aggressively sucks the dirt off the screen, similar to a vacuum cleaner, and are carried to the drain via the rinse valve. The dirt collector rotates, ensuring the entire screen is cleaned each cycle. The process takes a matter of seconds, with­out interruption of system flow.