Mueller Streamline CORED42 Copper Reducing Coupling

Product Description

The MUELLER STREAMLINE CORED42 is a copper reducing coupling designed to join two sections of copper pipe with differing diameters in a sweat-solder connection. It transitions from a 4-inch socket on one end to a 2-inch socket on the other, using a standard cup-by-cup (C x C) configuration. This fitting is installed in copper water supply, hydronic heating, and plumbing distribution systems where a permanent, pressure-rated reduction in pipe size is required. Licensed plumbers and pipefitters install this coupling as part of new construction and retrofit work.

This reducing coupling is suited for residential and commercial plumbing applications where copper pipe runs need to step down in diameter. Typical scenarios include main supply trunk reductions, branch connections, and hydronic loop distribution. The C x C end configuration requires both pipe ends to be cleaned, fluxed, and soldered per standard practice, making this a permanent mechanical joint appropriate for in-wall, in-ceiling, or mechanical room installations.

Key Features

• Transitions from 4-inch to 2-inch nominal copper pipe diameter
• Cup-by-cup (C x C) end configuration for sweat-solder installation
• Copper construction for corrosion resistance in potable water and hydronic systems
• Compatible with standard copper tubing sizes per ASTM specifications
• Suitable for permanent, pressure-rated plumbing joints

Compatibility

Designed as an OEM-style replacement and new-installation fitting for copper piping systems using 4-inch and 2-inch nominal diameter copper tube joined by sweat-solder methods.

Installation Notes

Installation should be performed by a licensed plumber in accordance with the International Plumbing Code (IPC) and applicable local codes. Shut off and depressurize the water supply and drain the affected line before cutting or soldering. Both pipe ends must be cut square, deburred, cleaned with emery cloth, and coated with appropriate flux before applying heat and solder. Do not use open-flame torches near combustible framing without a heat shield in place.

Technical Specifications

• Inlet Size: 4 inches
• Outlet Size: 2 inches
• End Connection Type: C x C (Cup by Cup, sweat-solder)
• Material: Copper

Standard Information

• Brand: MUELLER STREAMLINE
• Manufacturer Part Number: CORED42