(7) The Ashcroft L Series Pressure Switch is a single set point, adjustable differential pressure switch suitable for control. L Series Switches are currently being used in pulp and paper mills, refineries, chemical and petrochemical plants, dairies, breweries and waste water treatment plants, steel mills and other tough environments. Typical applications include pump or compressor control, paint spray equipment, boilers and burners, turbines, reverse osmosis systems, filters and presses.