Bk Mueller 511-342HC Malleable Iron Reducing Coupling

Product Description

The BK MUELLER 511-342HC is a malleable iron reducing coupling designed to connect pipes of two different diameters in threaded piping systems. It steps down from a 3/4-inch female thread to a 3/8-inch female thread, making it a standard component in gas, liquid, and low-pressure steam distribution lines. Rated at 300 psi for liquid and gas service and 150 psi for steam, this Class 150 fitting carries a galvanized finish for added corrosion resistance. Licensed plumbers and gas fitters install this type of fitting in both new construction and retrofit piping work.

This reducing coupling is suited for residential and light commercial piping applications where a threaded diameter reduction is required in-line. Typical installations include natural gas supply lines, compressed air distribution, and water piping systems. The threaded end connection allows for tool-only makeup without welding or soldering, which simplifies installation in tight or retrofit spaces. Its malleable iron construction handles the mechanical stress of pipe makeup and vibration common in mechanical rooms and utility chases.

Key Features

• Reduces from 3/4-inch to 3/8-inch female NPT threaded connection
• 300 psi pressure rating for liquid and gas service
• 150 psi pressure rating for steam service
• Class 150 malleable iron construction for durability under mechanical stress
• Galvanized finish provides corrosion resistance
• Threaded end connections allow tool-only installation with no welding or soldering

Compatibility

Designed as an OEM-style replacement or standard replacement fitting for Class 150 threaded malleable iron piping systems using NPT connections in gas, liquid, and low-pressure steam service.

Installation Notes

Installation should be performed by a licensed plumber or qualified gas fitter in accordance with applicable local codes, IPC, and IFGC requirements. Shut off and depressurize the line completely before disassembly or fitting makeup. Apply an approved thread sealant or PTFE tape rated for the service medium to all male threads before assembly. Do not over-torque malleable iron fittings, as the material is strong but not tolerant of extreme force that can crack the casting.