81Differential Pressure TransmittersPRESSUREDWYER INSTRUMENTS, INC. | dwyer-inst.com®WET/WET DIFFERENTIAL PRESSURE TRANSMITTERS±0.25% Accuracy, Quick Response, 2-Wire DesignSeries 645 Wet/Wet Differential Pressure Transmitters are designed for use with compatible gases and liquids which can be applied to both the pressure and reference ports. Quick response capacitance sensor delivers a 4 to 20 mA output signal proportional to differential pressure with ±.25% accuracy. The Series 645 transmitters are ideal for process control, filter condition monitoring, refrigeration equipment, pump speed control, HVAC equipment, and liquid level measurement. For ease of installation and maintenance, order optional 3-valve manifold assembly. Bleed ports allow for total elimination of air in the line and pressure cavities.FEATURES/BENEFITS• Versatile, high-accuracy device for liquid or gas supports designs requiring more precise measurements in support of application• Optional 3-way valve manifold supports simplifying installation or removal of transmitter without interrupting processAPPLICATIONS• Process control• Refrigeration equipment• HVAC equipment• Filter monitoring• Pump speed control• Liquid level measurement2 5/32 [54.61]3 1/64 [76.45]1-15/16 [49.35]LOWPRESSURE PORT3-1/16[77.59]1 [25.44]1/4 NPT BOTH SIDES1-3/32[27.98]1-63/64[50.50]1-1/2[38.16]1[25.44]BLEEDSCREWS2-7/16[62.01]HIGH PRESSURE PORTø7/8 KNOCKOUT INTENDED FOR A 1/2 I.D. CONDUIT CONNECTION SPECIFICATIONSService: Compatible gases or liquids on both pressure and reference sides.Wetted Materials: 17-4 PH stainless steel, 300 Series stainless steel, fluoroelastomer and silicone O-rings and bleed screw seals.Accuracy: ±0.25% FS (RSS).Temperature Limits: Operating: 0 to 175°F (-22 to 80°C); Storage: -65 to 260°F (-54 to 126°C).Pressure Limits: (High side) 1 to 5 psi: 20 x FS, 10 to 25 psi: 10 x FS, 50 psi: 5 x FS, 100 psi: 2.5 x FS; (low side) 2.5 x FS. Thermal Effects: (includes zero and span) ±0.02% FS/°F, 30 to 150°F (-1 to 65°C).Power Requirements: 11 to 30 VDC.Output Signal: 4 to 20 mA, 2-wire.Zero and Span Adjustments: Adjustable, ±1 mA, non-interactive.Response Time: 30 to 50 ms.Loop Resistance: 0 to 1000Ω.Electrical Connection: Barrier strip terminal block with conduit enclosure and .875˝ (22 mm) diameter conduit opening.Process Connection: 1/4˝-18 female NPT.Housing: Stainless steel/aluminum, NEMA 4X (IP56).Weight: 14.4 oz (0.4 kg).Agency Approvals: CE.3-VALVE MANIFOLD ASSEMBLYManifold: Brass.Valve Type: 90° on/off.Process Connection: 1/4˝-18 female NPT.Optional 3-Valve Manifold AssemblySERIES 645USA: California Proposition 65WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.govMODEL CHARTModelRange645-0645-1645-2645-3645-4645-5645-60 to 1 psid0 to 2 psid0 to 5 psid0 to 10 psid0 to 25 psid0 to 50 psid0 to 100 psidNote: For optional 3-valve manifold assembly, add -3V to end of model number.OPTIONSUse order code:DescriptionNISTCAL-PT1NIST traceable calibration certificateNext >