Merit Brass C112-0402 Reducing Coupling 1/4x1/8 Fnpt Class 125

Product Description

The MERIT BRASS C112-0402 is a brass pipe reducing coupling used to connect two female-threaded pipe ends of different diameters in a single inline fitting. It transitions from a 1/4-inch FNPT port to a 1/8-inch FNPT port, making it a compact solution for reducing pipe size within a threaded piping system. Rated at Class 125, this coupling is suited for low-to-medium pressure service in gas, water, and general fluid distribution applications. Plumbers, pipefitters, and HVAC technicians reach for this type of fitting when downsizing a branch line or adapting a threaded port to a smaller-diameter component. The all-brass construction offers corrosion resistance and reliable thread engagement on standard NPT pipe.

This reducing coupling is typically installed in residential and light commercial piping systems where a 1/4-inch line must transition to a 1/8-inch threaded connection. Common applications include instrument tubing, pressure gauge ports, pilot gas lines, and small-diameter water or air supply lines. Both ends use standard FNPT (female national pipe taper) threads, allowing direct connection to any male NPT-threaded pipe, nipple, or fitting of the corresponding size. Its compact, lightweight form factor fits into tight spaces where an inline reducer is preferred over a combination of separate adapters.

Key Features

• Reduces from 1/4-inch FNPT to 1/8-inch FNPT in a single inline fitting
• Class 125 pressure rating suitable for general-purpose fluid and gas service
• All-brass construction provides corrosion resistance and durable thread integrity
• FNPT x FNPT end connections accept standard male NPT-threaded pipe on both sides
• Lightweight at 0.1 pounds — minimal load on fittings and instrument ports

Compatibility

Designed as an OEM-style replacement or new-installation fitting for threaded brass piping systems using standard NPT connections, consistent with Class 125 service requirements.

Installation Notes

Installation of this fitting is typically performed by a licensed plumber or pipefitter. Shut off and depressurize the system completely before removing or installing any threaded pipe fitting. Apply an appropriate thread sealant or PTFE tape to the male NPT threads before making up the joint — do not apply sealant to female threads. Tighten to hand-tight plus the appropriate number of turns for the pipe size; avoid over-tightening brass fittings, which can crack the body or distort the threads.