Dwyer 645-3 Transmitter

Core Performance & Industrial Application

The Dwyer 645-3 is a Series 645 wet/wet differential pressure transmitter, range 0-10 psid, using a capacitive sensing element for compatible gases or liquids on both ports.

4-20 mA two-wire output; ±0.25% FS (RSS) accuracy; 30-50 ms response; non-interactive zero/span adjustment ±1 mA.

NEMA 4X (IP56) stainless/aluminum enclosure; 1/4-18 female NPT process connections; bleed ports for cavity air purge.

It serves filter monitoring, refrigeration, pump speed control, HVAC and liquid level DP measurement.

Technical Specifications

▶ Product type: Wet/wet differential pressure transmitter

▶ Brand: Dwyer Instruments

▶ Model: 645-3 (range 0-10 psid)

▶ Accuracy: ±0.25% FS (RSS)

▶ Output: 4-20 mA DC, 2-wire; loop resistance 0-1000 Ω

▶ Supply: 11-30 VDC

▶ Response: 30-50 ms; zero/span adjustable ±1 mA, non-interactive

▶ Process connection: 1/4-18 female NPT; wetted 17-4PH / 300-series SS, FKM/silicone O-rings

▶ Overpressure: Per high-side rating; low side 2.5× FS

▶ Environment: 0~80℃ operating; -54~126℃ storage; NEMA 4X / IP56

▶ Electrical: Barrier strip terminal block; 22 mm conduit entry

▶ Feature: Dual wet ports, bleed screws, optional 3-valve manifold

▶ Note: Manifold option and calibration tag confirmed from nameplate before ordering

▶ Country of origin: USA

▶ Compliance: CE certification

Industry Applications

Applied in filter condition monitoring, refrigeration, HVAC, pump control and liquid-level DP measurement spare replacement.

Note: Confirm range, manifold option and calibration tag against nameplate before ordering