Bk Mueller 511-320HC Malleable Iron Reducing Coupling

Product Description

The BK MUELLER 511-320HC is a malleable iron reducing coupling designed to connect two threaded pipe segments of different diameters in a single inline fitting. At 3/8 inch by 1/8 inch, it reduces pipe size while maintaining a secure, leak-resistant threaded connection. Rated at 300 psi for liquid and gas service and 150 psi for steam, this Class 150 fitting meets the demands of high-pressure plumbing, HVAC piping, and gas distribution applications. The galvanized finish provides corrosion resistance for long service life in both exposed and concealed installations. Licensed plumbers and pipefitters are the primary installers.

This reducing coupling is suited for residential and light commercial piping systems where a threaded inline pipe reduction is required. Common applications include gas supply lines, compressed air systems, steam distribution, and hydronic heating lines. The NPT threaded ends allow direct connection to standard pipe and fittings without additional adapters when transitioning from 3/8 inch to 1/8 inch pipe.

Key Features

• Reduces 3/8 inch pipe to 1/8 inch pipe in a single threaded fitting
• 300 psi liquid and gas pressure rating for high-demand service
• 150 psi steam pressure rating for steam distribution systems
• Galvanized finish for corrosion resistance in wet or humid environments
• Class 150 malleable iron construction for durability under pressure cycling
• Threaded end connections compatible with standard NPT pipe

Compatibility

Designed as an OEM-style replacement or new-installation fitting for standard NPT-threaded malleable iron piping systems in residential and commercial plumbing, gas, and steam applications.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable codes including the IPC and IFGC. Shut off all gas or fluid supply and relieve system pressure completely before removing or installing any pipe fitting. Apply an appropriate thread sealant or PTFE tape to the NPT threads before assembly, and tighten to a wrench-tight fit without over-torquing malleable iron threads. Inspect for leaks after restoring system pressure.