dwyer-inst.comDWYER INSTRUMENTS, INC.®T: 219-879-8000 | F: 219-872-9057 | info@dwyermail.com 800-872-9141FEATURES/BENEFITS• Explosion-proof and weatherproof housing provides device protection for outdoor use or harsh environment operation• External set point screw provides easy access without opening or disassembling enclosure• Easily accessible electrical connection simplifies the installationAPPLICATIONS• HVAC applications• Process applications• All-weather applicationsDESCRIPTIONThe Series 1950 Explosion-Proof Differential Pressure Switch combines the best features of the popular Dwyer® Series 1900 Pressure Switch with an integral explosion-proof and weatherproof housing, making it an exceptional value for either application. It is CE, UL and CSA listed, FM approved for use in Class I, Div 1, Groups C and D, Class II Groups E, F, and G and Class III hazardous atmospheres NEMA 7 & 9. Rain tight NEMA 3 (IP54), weatherproof 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 in w.c. (0.0075 to 5 kPa) and from .5 to 60 psi (0.035 to 3.5 bar). The unit is very light and compact - about half the weight and bulk of other explosion-proof or weatherproof switches with separate enclosures. SPECIFICATIONS Service Air and non-combustible, compatible gases.Wetted MaterialsConsult factory.Temperature Limits-40 to 140°F (-40 to 60°C); 0 to 140°F (-17.8 to 60°C) for 1950P-8, 15, 25, and 50. -30 to 130°F (-34.4 to 54.4°C) for 1950-02.Pressure Limits (Continuous)1950’s - 45 in w.c. (0.11 bar); 1950P’s - 35 psi (2.41 bar); 1950P-50 only - 70 psi (4.83 bar). Surge: 1950’s - 10 psi (0.69 bar), 1950P’s - 50 psi (3.45 bar), 1950P-50 only - 90 psi (6.21 bar).Enclosure RatingNEMA 3 (IP54), NEMA 7 & 9.Switch TypeSingle-pole double-throw (SPDT).Electrical Rating15 A @, 125, 250, 480 VAC, 60 Hz. Resistive 1/8 HP @ 125 VAC, 1/4 HP @ 250 VAC, 60 Hz.Electrical Connections3 screw type, common, normally open and normally closed.Process Connections1/8˝ female NPT.Mounting OrientationDiaphragm in vertical position. Consult factory for other position orientations.Set Point AdjustmentScrew type on top of housing.Weight3.25 Ib (1.5 kg); 1950-02 model, 4.4 lb (2 kg).Agency ApprovalsCE, CSA, FM, UL.SERIES 1950 | EXPLOSION-PROOF DIFFERENTIAL PRESSURE SWITCHImportant Notice: Dwyer Instruments, Inc. reserves the right to make changes to or discontinue any product or service identified in this publication without notice. Dwyer advises its customers to obtain the latest version of the relevant information to verify, before placing any orders, that the information being relied upon is current.®dwyer-inst.comDWYER INSTRUMENTS, INC.DS-1950 Rev. 1 | 11/18T: 219-879-8000 | F: 219-872-9057 | info@dwyermail.com 800-872-9141DIMENSIONSWIRING DIAGRAMHOW TO ORDERSWITCH TYPE1950: Pressure switch - inches w.c.1950P: Pressure switch - PSIDRANGE-02: 0.03 - 0.10 in w.c. -00: 0.07 - 0.15 in w.c.-0: 0.15 - 0.5 in w.c. -1: 0.4 - 1.6 in w.c. -5: 1.4 - 5.5 in w.c. -10: 3.0 - 11.0 in w.c. -20: 4.0 - 20.0 in w.c. -2: 0.5 - 2.0 psid-8: 1.5 - 8.0 psid-15: 3.0 - 15.0 psid-25: 4.0 - 25.0 psid-50: 15.0 - 50.0 psidMICRO SWITCH TYPE-2: 10G mica silver contact*-6: 10G phenolic gold contact-M: 10C phenolic silver contactOPTIONS-AT: Aluminum tag-PRESET: Preset-ST: Stainless steel tagDIAPHRAGM MATERIALB: Buna-NF: Flurosilicone*N: NeopreneS: SiliconeV: Fluroelastomer*The 2F is standard1950-02-2S-ATUse the bold characters from the chart below to construct a product code.EXTERNALGROUND[2] Ø17/64 [6.75] MOUNTINGHOLES EQUALLY SPACED ONA 4-7/8 [123.83] B.C.RANGE ADJUSTMENT SCREW5-7/16[138.13]1/2 FEMALE NPTELECTRICAL CONNECTIONVENT DRAINPLUGCAPTIVE SCREW1/8 FEMALE NPTLOW PRESSURE CONNECTION1-15/32 [37.30]3/8 [9.53]27/32 [21.43]27/32[21.43]3-1/2 [88.90]1-23/32 [43.64]3/8 [9.53]1/8 FEMALE NPT HIGH PRESSURE CONNECTIONNext >