The Greystone Model DPF073VB Differential Wet-to-Wet Pressure Transmitter with Integrated 3-Way Valve Bracket Assembly, engineered and manufactured by Greystone Energy Systems Inc. in Moncton, New Brunswick, Canada, is an industrial-grade wet differential pressure measurement package designed specifically for commercial HVAC hydronic loops, central chiller plants, and pumping infrastructure.

Model Number Code Architecture Breakdown (DPF073VB):
- DP: Wet-to-Wet Differential Pressure Transmitter Series.
- F: Industrial grey polycarbonate enclosure featuring a hinged gasketed cover with a snap latch, supplied complete with an integrated 1/2" NPT to M16 thread adapter and a liquid-tight cable gland fitting.
- 07: Metric multi-range configuration offering field-selectable ranges: 1 Bar, 2 Bar, 5 Bar, or 10 Bar (100, 200, 500, 1000 kPa).
- 3VB: Complete factory-assembled 3-Way Valve Bracket Assembly (Bypass / Equalizer Manifold).

Key Engineering Features & Operational Advantages:
- Factory-Assembled 3-Way Valve Manifold Bracket (3VB): Incorporates high-pressure isolation valves on the High and Low ports along with a central equalizing/bypass valve mounted to a heavy-duty bracket. During initial installation, startup, and commissioning, opening the equalizer valve eliminates one-sided pressure spikes that can damage differential pressure diaphragms. Technicians can perform zero calibration or isolate the transmitter for maintenance without depressurizing or draining the main piping system.
- Robust 17-4 PH Stainless Steel Wetted Sensors: Utilizes high-stability isolated piezoresistive silicon sensing technology with 17-4 PH stainless steel wetted diaphragms. The sensors resist corrosion from chilled water, heating water, glycol solutions, and light oils, delivering an accuracy of ±1% F.S.O. and accommodating line working pressures up to 200 psi (13.8 bar).
- 4 Switch-Selectable Metric Pressure Ranges: Features convenient on-board switch selection between 1 Bar, 2 Bar, 5 Bar, and 10 Bar. This multi-range design simplifies inventory logistics and enables precise field recalibration to match actual system operating delta-P.
- 3-in-1 Universal Analog Output Architecture: Easily configured for 4 to 20 mA current loop (2-wire connection) or 0 to 5 VDC / 0 to 10 VDC voltage outputs (3-wire connection), ensuring immediate compatibility with all major commercial DDC controllers, PLC platforms, and BMS systems.
- Pushbutton Auto-Zero Functionality: When the bypass equalizing valve is open (applying equal pressure to both ports), pressing the on-board Auto-Zero pushbutton prompts the internal microprocessor to calculate and store a true zero baseline, eliminating manual potentiometer adjustments.
- Rugged IP65 / NEMA 4X Polycarbonate Enclosure (F-Style): Molded from UL94-V0 flame-retardant, UV-resistant grey polycarbonate with a continuous perimeter sealing gasket. The hinged lid allows rapid one-handed wiring access without dropping cover screws. Supplied complete with a 1/2" NPT to M16 thread adapter and liquid-tight cable gland to protect internal circuitry against mechanical room condensation and moisture.

Typical Industrial Applications:
- Chilled water and condenser water differential pressure tracking across central chiller barrels to verify minimum flow rates and prevent evaporator freeze-up.
- Closed-loop secondary hydronic pump differential head control to regulate variable frequency drives (VFD Pump Control).
- Monitoring particulate loading and clogging across water strainers, sand filters, and plate-and-frame heat exchangers.
- Verifying pressure drops across automatic pressure-independent control valves (PICV) and hydronic balancing stations.

• Manufacturer: Greystone Energy Systems Inc.
• Country of Origin: 100% Canada (Made in Canada)
• Product Line: DP Series Differential Wet Pressure Transmitters
• Model Designation: DPF073VB
• Sensing Technology: Dual isolated piezoresistive silicon sensors
• Wetted Materials: 17-4 PH Stainless Steel diaphragms and manifold fittings
• Media Compatibility: Liquids and gases compatible with 17-4 PH stainless steel (treated water, chilled water, hot water, glycol mixtures, light oils)
• Pressure Ranges (Switch-Selectable): 1 Bar, 2 Bar, 5 Bar, and 10 Bar (100, 200, 500, 1000 kPa)
• Integrated Valve Package: Heavy-duty 3-Way Valve Bracket Assembly (High Block, Low Block, and Equalizer/Bypass valves)
• Measurement Accuracy: ±1% F.S.O. (Full Scale Output) across selected range
• Response Time: 250 milliseconds (250 ms)
• Maximum Working Line Pressure: 200 psi (13.8 bar)
• Proof Pressure: Maximum 2x highest selected range
• Burst Pressure: Maximum 5x highest selected range
• Analog Output Signals (Field-Selectable):
  - Current Loop: 4 - 20 mA (2-wire configuration)
  - Voltage Output: 0 - 5 Vdc or 0 - 10 Vdc (3-wire configuration)
• Output Drive Capability:
  - Current Loop: 500 Ω maximum @ 24 Vdc
  - Voltage Output: 10 kΩ minimum
• Zero Calibration: Tactile on-board pushbutton auto-zero functionality
• Power Supply Requirements: 24 Vac/dc ±10% (non-isolated half-wave rectified)
• Current Consumption: Current mode: 20 mA maximum; Voltage mode: < 6 mA
• Hydraulic Process Ports: 1/4" NPT Female ports on the 3-way manifold assembly
• Electrical Wiring Termination: Screw terminal block accommodating 14 to 22 AWG wiring
• Conduit & Cable Entry: 1/2" NPT conduit knockout with included 1/2" NPT to M16 adapter and liquid-tight cable gland
• Enclosure Construction: Grey Polycarbonate, UL94-V0 flame retardant, hinged cover with latch and perimeter gasket
• Ingress Protection Rating: IP65 / NEMA 4X (sealed against dust and washdown water jets)
• Process Fluid Temperature Range: -20°C to +85°C (-4°F to +185°F)
• Operating Ambient Conditions: 0°C to +50°C (32°F to +122°F), 5% to 95% RH non-condensing
• Quality & Safety Approvals: CE marked, RoHS compliant, ISO 9001 certified manufacturing
• Total Assembly Net Weight (Transmitter + Valve Manifold): Approximately 1.8 kg (4.0 lbs).