Model AFS-398-112 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-398-112 has a field adjustable set point range of 0.05″ wc to 2.0″ 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 two barbed sample line connectors that accept flexible tubing.