Bk Mueller 511-374HN Malleable Iron Reducing Coupling

Product Description

The BK MUELLER 511-374HN is a malleable iron reducing coupling designed to connect pipes of two different diameters in threaded piping systems. Sized at 1-1/2 x 3/4 inches, this Class 150 galvanized fitting is rated for 300 psi on liquid and gas service and 150 psi on steam service. Licensed plumbers and pipefitters rely on this type of fitting for reducing line size within distribution systems across residential and light commercial applications. The galvanized finish provides corrosion resistance in damp or exposed environments.

This reducing coupling is suited for use in threaded iron pipe systems carrying water, gas, or steam. Typical installations include branch reductions in water supply headers, gas distribution lines, and steam systems where a transition from 1-1/2 inch to 3/4 inch pipe is required. The Class 150 rating makes it appropriate for standard-pressure service in commercial mechanical rooms, boiler rooms, and residential utility spaces.

Key Features

• Reduces from 1-1/2 inch to 3/4 inch in a single threaded fitting
• Rated 300 psi for liquid and gas service
• Rated 150 psi for steam service
• Class 150 malleable iron construction for strength and durability
• Galvanized finish for corrosion resistance in wet or exposed piping environments
• Threaded end connections compatible with standard NPT pipe threads

Compatibility

Designed as an OEM-style replacement or standard component for Class 150 malleable iron threaded piping systems handling liquid, gas, or steam service.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable codes such as the IPC or IFGC. Shut off and depressurize the line completely before removing or installing any threaded fittings. Apply appropriate thread sealant or PTFE tape to male threads before assembly. Do not overtighten, as malleable iron threads can crack under excessive torque.