ETL Approved: Electronic Components: Home Improvement. Dwyer Differential Pressure Switch. adjustment knob and meeting the UL508 standard make the EDPS the perfect choice for H.V.A.C. applications. APPLICATIONS Monitoring air filters and ventilators Monitoring industrial cooling-air circuits Overheating protection for fan heaters Monitoring flows in ventilation ducts Controlling air and fire-protection dampers Frost protection for heat exchanges 。 。 。. 1/2" NPT, .20-2.00' w.c., ETL Approved: Electronic Components: Home Improvement. The Series EDPS Adjustable Differential Pressure Switch is designed for pressure, vacuum, Dwyer Differential Pressure Switch. and Differential Pressures. The dual scaled adjustment knob in inches water column and pascals allows changes to the switching pressure to be made without a pressure gage. The EDPS is available with settings from 0.08? w.c. (20 Pa) up to 16? w.c. (4000 Pa). The silicone diaphragm and PA 6.6 body make the series EDPS ideal for use with air and other noncombustible gases. The compact size, .20-2.00" w.c., 1/2' NPT, EDPS-03-1-N, EDPS-03-1-N.