Series 1950 Explosion-Proof Differential Pressure Switches Compact, low cost, explosion-proof and weatherproof. Dimensional Enlargement Model 1950 Explosion-Proof Differential Pressure Switch combines the best features of the popular Dwyer series 1900 with an integral explosion-proof and weather-proof housing, making it an exceptional value for either application. It is U.L. and C.S.A. listed, F.M. approved for use in Class I Groups C and D, Class II Groups E, F, and G and Class III hazardous atmospheres (NEMA 7 & 9). Weather-proof features include a drain plug and O-ring seal in cover. Electrical connections are easily made by removing front cover. For convenience the set point adjustment screw is located on the outside of the housing. Twelve models offer set points from .03 to 20 inches W.C. and from .5 to 60 PSI. The unit is very light and compact - about half the weight and bulk of other explosion-proof or weather-proof switches with separate enclosures. PHYSICAL DATA Temperature Limits: -40°F to 140°F. 0°F to 140°F for 1950P-8, 15, 25, and 50 -30°F to 130°F for 1950-02 Maximum Surge Pressure: 1950-10 PSI, 1950P-50 PSI 1950P-50 only - 90 PSI Rated Pressure: 1950 - 45 IN. W.C., 1 950P - 35 PSI 1 950P-50 only - 70 PSI Pressure Connections: 1/8" NPT. Electrical Rating: 15 amps, 125, 250, 480 volts, 60 Hz. A.C. Resistive 1/8 H.P. @ 125 volts, 1/4 H.P. @ 250 volts, 60 Hz. A.C. Wiring Connections: 3 screw type; common, norm. open and norm. closed. Conduit Connection: 1/2" NPT. Set Point Adjustment: Screw type on top of housing. Field adjustable. Housing: Anodized cast aluminum. Diaphragm: Molded fluorosilicone rubber. 02 model, silicone on nylon. Calibration Spring: Stainless steel. Installation: Mount with diaphragm in vertical position. Weight: 3 1/4 lbs. 02 model, 4 lbs., 7 oz. FACTORY STOCKED MODELS Model Number Operating Range PSI Approximate Dead Band At Min. Set Point At Max. Set Point 1950P-2 1950P-8 1950P-15 1950P-25 1950P-50 .5 to 2.0 1.5 to 8.0 3.0 to 15.0 4.0 to 25.0 15.0 to 50.0 0.3 PSI 1.0 PSI 0.9 PSI 0.7 PSI 1.0 PSI 0.3 PSI 1.0 PSI 0.9 PSI 0.7 PSI 1.5 PSI CAUTION: For use only with air or compatible gases. Applications with hazardous atmospheres and a single positive pressure may require special venting. FACTORY STOCKED MODELS Model Number Operating Range Inches W.C. Approximate Dead Band At Min. Set Point At Max. Set Point 1950-02 1950-00 1950-0 1950-1 1950-5 1950-10 1950-20 0.03 to 0.10 0.07 to 0.15 0.15 to 0.5 0.4 to 1.6 1.4 to 5.5 3.0 to ll.0 4.0 to 20.0 0.025 0.04 0.10 0.15 0.3 0.4 0.4 0.05 0.05 0.15 0.20 0.4 0.5 0.6