Mueller Streamline CORED3438 Copper Reducing Coupling

Product Description

The MUELLER STREAMLINE CORED3438 is a copper reducing coupling designed to connect two copper tubes of different diameters in a sweat-soldered (C x C) configuration. This fitting transitions a 3/4-inch line down to a 3/8-inch line, making it a standard component in residential and light commercial plumbing, HVAC refrigerant piping, and hydronic systems. Plumbers and HVAC technicians install this type of fitting wherever a pipe size reduction is required inline without the use of threaded or press connections.

This reducing coupling is suited for potable water distribution, drain and supply rough-in work, refrigerant line sets, and hydronic heating or cooling piping. The C x C end configuration means both ends accept standard copper tube and are joined by soldering, following conventional sweat-fitting practice. It is appropriate for use in tight spaces where a threaded fitting adapter would add unnecessary bulk or potential leak points.

Key Features

• Reduces from 3/4 inches to 3/8 inches in a single inline fitting
• C x C (sweat) end connections on both sides
• Copper construction for corrosion resistance and long service life in wet environments
• Compatible with standard silver-bearing or lead-free solder per code requirements
• Compact profile for installation in confined spaces

Compatibility

Designed as an OEM-style replacement or new-installation fitting for residential and light commercial copper piping systems requiring an inline reduction from 3/4-inch to 3/8-inch tubing with sweat connections.

Installation Notes

Installation requires a licensed plumber or qualified HVAC technician in jurisdictions where copper sweat work is regulated. Shut off the water supply or isolate the refrigerant circuit and relieve system pressure before cutting into any existing line. Tube ends must be cut cleanly, deburred, and cleaned with emery cloth or a fitting brush before flux application and soldering. Follow local plumbing codes, IPC guidelines, and applicable refrigerant handling regulations when selecting flux and solder alloy.

Technical Specifications

• Inlet Size: 3/4 inches
• Outlet Size: 3/8 inches
• Connection Type: C x C (sweat)
• Material: Copper

Standard Information

• Brand: MUELLER STREAMLINE
• Manufacturer Part Number: CORED3438