Series DNS2 Air Flow Pressure Sensing Switches are the best solution for applications that require dual set points. In addition, DNS2 switches have a narrow switching differential, and low set point tolerance over a wide operating temperature and set point range. Factory-calibrated and sealed set points are available from 0.05′′ to 10.0′′ wc. DNS2TM switches can be used to sense positive, negative or differential air pressure. Typically, DNS2 switches are applied to two-stage furnaces where high fire and low fire set points are required. Each of the two glass-filled polycarbonate housings contains a sensing diaphragm and an integral snap-acting switch. One or two sample line connectors are located on either or both sides of the diaphragm to accept air sample connections. The snap action switch can be actuated by a pressure or vacuum air flow, or by a pressure or vacuum differential.