1/2" Combination Boiler Feed Valve and Backflow, NPT x NPT

Taco 3450-2 Combination Boiler Feed Valve and Backflow Preventer – 1/2" Union Sweat – Technical Information

The Taco 3450-2 Combi Valve is a professional-grade, dual-function hydronic component engineered to integrate system make-up and backflow prevention into a single, serviceable body assembly. This combination valve merges a cartridge-style pressure regulating boiler feed valve with a dual check backflow preventer featuring an atmospheric vent, delivering compact installation and reliable operation. Designed for hydronic heating systems, the 3450-2 ensures consistent system pressure control while preventing system water from contaminating the potable supply. With its modular cartridge design, all internal components can be serviced or replaced without draining the heating loop, simplifying maintenance and minimizing downtime in field applications.

Technical Specifications

• Manufacturer: Taco Comfort Solutions
• Model Number: 3450-2
• Product Type: Combination Boiler Feed Valve and Backflow Preventer
• Connection Type: Union Sweat
• Connection Size: 1/2 inch
• Valve Configuration: Dual Check Backflow with Atmospheric Vent and Boiler Feed Regulator
• Body Material: Brass
• Operating Pressure (Maximum): 125 PSI
• Cold Fill Pressure Range: 10–25 PSI Adjustable
• Factory Preset Pressure: 12 PSI
• Operating Temperature Range: 33°F to 225°F (0.5°C to 107°C)
• Valve Type: Cartridge-Style Replaceable Components
• Regulation Feature: Dial-in Pressure Setting with Adjustable Indicator
• Relief Feature: Atmospheric Vent on Backflow Cartridge
• Feed Valve Function: Automatic System Fill and Pressure Maintenance
• Backflow Function: Dual Check Protection to Prevent Reverse Flow
• Reset Type: Auto-Reset Purge Valve
• Installation Orientation: Horizontal or Vertical Mounting
• Applications: Closed-Loop Hydronic Heating Systems, Boiler Feed Assemblies
• Maintenance: Cartridge Replacement Without System Drain Required
• Compliance: Meets ASSE and CSA Standards for Backflow Prevention Devices
• Country of Manufacture: USA

Performance and Application Features

• Integrates boiler feed pressure regulation and backflow prevention into a single, compact body design.
• Dual check backflow mechanism with atmospheric vent prevents system water contamination in supply lines.
• Boiler feed valve automatically maintains desired system pressure and refills as necessary.
• Cartridge-based modular construction allows in-place servicing without system drainage.
• Adjustable dial-in pressure regulator enables precise calibration for specific system requirements.
• Auto-reset purge design simplifies air and debris clearing during commissioning and maintenance.
• Constructed from high-grade brass for long-term resistance to corrosion and pressure cycling fatigue.
• Compact footprint allows direct integration into hydronic manifolds or boiler supply assemblies.
• Compatible with both residential and light commercial hydronic heating configurations.
• Engineered for stability under fluctuating inlet pressures to maintain constant system fill pressure.

Professional Summary

The Taco 3450-2 Combination Feed Valve and Backflow Preventer provides professional contractors with a durable, field-serviceable solution for hydronic boiler systems requiring automatic pressure maintenance and potable water protection. Its dual check and atmospheric vent design ensures compliance with backflow prevention standards, while the precision regulator maintains consistent fill pressure for closed-loop systems. The cartridge-based layout enables simplified maintenance without system shutdown, reducing labor time on site. Built from corrosion-resistant brass and engineered for long service life, the Taco 3450-2 sets a benchmark for reliability, efficiency, and serviceability in modern hydronic installations.