KP-A pressure switches for use in refrigeration and air conditioning systems with fluorinated refrigerants and ammonia (R717/NH3). Materials in contact with the medium in steel, primarily 18/8 stainless steel (to EN 10008-2). KP pressure switches are designed to protect refrigeration systems from excessively high discharge pressures, excessively low suction pressures, to start/stop compressors or to operate fans of aircooled condensers.