Models RFS-4001-025 and RFS-4001-031 Differential Pressure Switches are general-purpose, airflow-proving switches designed for HVAC and building automation applications. They may be used to sense positive, negative, or differential air pressure. The plated housing contains a diaphragm, calibration spring and snap-acting switch. The Model RFS-4001-025 pressure connections located on each side of the diaphragm, accept copper or flexible 1/4" OD tubing. The Model RFS-4001-031 has tri-barb connectors that accept 1/8", 1/4", and 5/16" ID flexible tubing. An enclosure cover guards against accidental contact with the live-switch terminal screws and the set point-adjusting screw. The enclosure will accept a 1/2" conduit connection. FEATURES Two-year warranty Adjustable set point Knockout for 1/2" conduit Enclosed terminals Compression or barb fittings SPECIFICATIONS Set point range 0.15" to 5.0" W.C. (37.3 to 1245 Pa) Differential Progressive, increasing from 0.05" WC at minimum setpoint to 0.3" WC at maximum setpoint Mounting position Diaphragm in any vertical plane, avoid upward pressure connections Media compatibility Air or gases that will not degrade silicone Contacts SPDT Electrical rating 300 VA pilot duty @ 115-277 VAC, 15A non-inductive to 277 VAC Electrical connections Screw teminals with cup washers Pressure connections RFS-4001-025 1/4" compression, suitable for use with 1/4" copper or plastic tubing RFS-4001-031 Tri-barb connectors for 1/8", 1/4" and 5/16" ID tubing Max overpressure 0.5 psig (3.5 kPa) Operating temp -40to 180F (-40 to 82C) Weight 14 oz. (0.4 kg) Approval UL, CUL Life 100,000 cycles minimum @ max pressure and at max rated load