Merit Brass 118-20 Countersunk Plug 1-1/4 in Mnpt Fnpt

Product Description

The MERIT BRASS 118-20 is a brass countersunk plug designed to close off threaded pipe openings in plumbing, mechanical, and fluid-handling systems. It features male NPT (MNPT) external threads and a female NPT (FNPT) countersunk socket at the head, allowing the plug to sit flush or below the surface of a threaded fitting or manifold. Rated at Class 125, this plug is suited for low-to-medium pressure service in water, oil, and general fluid applications. At 0.34 pounds and sized for 1-1/4 inch connections, it provides a solid, compact seal point for capping unused ports. Licensed plumbers and pipefitters install this type of fitting during system assembly, maintenance, and testing.

This countersunk plug is used in residential and commercial plumbing systems, hydronic heating distribution manifolds, compressed air headers, and industrial piping where a low-profile port closure is required. The MNPT x FNPT configuration makes it compatible with standard NPT-threaded pipe, fittings, and manifold bodies. Its countersunk profile allows it to recess into a tapped hole, keeping connections tidy in close-clearance installations where a raised hex plug would interfere with adjacent components.

Key Features

• Countersunk profile sits flush or recessed in tapped fittings and manifolds
• MNPT x FNPT threaded connection for standard NPT pipe compatibility
• Class 125 pressure rating for low-to-medium pressure fluid service
• Solid brass construction provides corrosion resistance in water and oil service
• 1-1/4 inch fitting size for common mid-range pipe port closures

Compatibility

Designed as an OEM-style replacement or new-installation fitting for standard NPT-threaded pipe systems and manifolds requiring a countersunk plug closure at 1-1/4 inch port size.

Installation Notes

Installation is performed by a licensed plumber or pipefitter using a pipe wrench or appropriately sized socket. Always depressurize and drain the system before removing or installing pipe plugs. Apply thread sealant tape or pipe dope to the MNPT threads in accordance with local plumbing codes before threading the plug into the port. Do not overtighten brass fittings, as brass threads can gall or crack under excessive torque.