Model AFS-240 is a general purpose proving switch designed for HVAC and Energy Management applications. It can be used to sense positive, negative, or differential air pressure. The plated housing contains a diaphragm, a calibration spring and a snap-acting SPDT switch. The AFS-240 has a field adjustable set point range of 0.05″ wc to 12.0″ wc. The screw terminals are protected by an enclosure that accepts 1/2″ conduit. This switch has an SPDT contact arrangement. It is equipped with compression ferrule and nut sample line connectors located on each side of the diaphragm that accept ¼” OD rigid tubing. This switch is suitable for surface mounting to a flange via the 7⁄16 – 24 UNS externally threaded connector. A mounting nut and self-aligning ferrule are provided.