Nibco 3992336851 Manual Circuit Balancing Valve 1/2 Inch Npt

Product Description

The NIBCO 3992336851 is a manual circuit balancing valve in the FLO-BOSS MLF series, designed for hydronic balancing applications in closed-loop heating and cooling systems. This valve allows technicians to set and lock flow rates circuit by circuit, helping to achieve proper system balance without the need for electronic controls. The brass body construction and PTFE-lined trim deliver durability in demanding water-based systems. Rated to 300 psi and 260 degrees F, this valve handles the pressure and temperature conditions found in most commercial and residential hydronic installations. The 1/2 inch NPT end connections make it compatible with standard threaded pipe configurations.

This valve is suited for hydronic heating and chilled-water distribution systems where individual circuit flow control is required. It is used in commercial and light-commercial HVAC applications, including fan coil units, radiant floor systems, and terminal unit piping. Installation typically occurs during system commissioning or retrofit balancing work. The T-1810-LF series designation indicates a lead-free compliant construction, meeting requirements for potable water contact where applicable, though this valve is most commonly specified in closed hydronic loops.

Key Features

• Manual circuit balancing for closed-loop hydronic systems
• 300 psi maximum working pressure
• 260 degrees F maximum operating temperature
• 1/2 inch NPT threaded end connections
• Brass body with brass and PTFE trim for corrosion resistance
• EPDM seals rated for hydronic service
• Lead-free compliant construction per T-1810-LF series designation

Compatibility

Designed as an OEM-style replacement or new-installation balancing valve for 1/2 inch NPT threaded hydronic piping systems. Inlet to outlet length is 3.46 inches and top to inlet center dimension is 4.06 inches; verify clearance before installation.

Installation Notes

Installation should be performed by a licensed plumber or qualified HVAC piping technician. Shut off system pressure and drain the affected circuit section before threading the valve into the line. Use appropriate thread sealant compatible with hydronic system fluids and EPDM seals. Follow local plumbing codes and ASHRAE hydronic system commissioning guidelines when setting circuit flow rates.