Merit Brass X119-12 Brass Pipe Locknut 3/4 in Fnpt

Product Description

The MERIT BRASS X119-12 is a 3/4 inch brass pipe locknut designed for threaded pipe connections in plumbing, HVAC, and industrial piping systems. It features female NPT (FNPT) ends and a Class 125 pressure rating of 125 psi. Locknuts are used to secure fittings, valves, or other components against a panel, bulkhead, or adjacent fitting by threading onto the male-threaded pipe or fitting body and tightening down to create a rigid, leak-resistant mechanical hold. The brass construction provides corrosion resistance suitable for water, air, and many common fluid service applications. Licensed plumbers and pipefitters are the primary installers of this type of fitting.

This locknut is suited for residential and light commercial plumbing, hydronic heating, and general-purpose piping applications where a 3/4 inch FNPT threaded connection is required. It is commonly installed at panel penetrations, tank fittings, and valve assemblies where a locking mechanism is needed to prevent loosening or rotation of a threaded fitting body. The brass material makes it compatible with copper and brass piping systems as well as many threaded iron and steel assemblies in low-to-moderate pressure service.

Key Features

• 3/4 inch FNPT threaded ends for standard NPT pipe compatibility
• Class 125 pressure rating at 125 psi for low-to-moderate pressure systems
• Brass construction offers corrosion resistance in water and air service
• Threaded connection type for tool-assisted hand installation without soldering
• Compact, lightweight design at 0.13 pounds

Compatibility

Designed as an OEM-style replacement or new-installation locknut for 3/4 inch FNPT threaded pipe systems rated to Class 125 service conditions.

Installation Notes

Installation is performed by a licensed plumber or qualified pipefitter in accordance with applicable IPC and local plumbing codes. Shut off and depressurize the pipe system completely before removing or installing any threaded fittings. Use appropriate pipe thread sealant or PTFE tape on male threads to ensure a leak-free joint, and tighten with the correct wrench size to avoid over-torquing the brass fitting body. Do not exceed the rated working pressure of 125 psi for this fitting class.