Mueller Streamline W 01321 Copper Reducer 5/8x3/8

Product Description

The MUELLER STREAMLINE W 01321 is a copper fitting reducer designed to transition between two different tube sizes in a single sweat-connection assembly. It reduces from a 5/8-inch fitting end to a 3/8-inch copper (C) end, allowing technicians to step down line sizes within refrigerant, plumbing, or hydronic piping systems. The fitting-to-copper (Fitting x C) configuration means one end accepts a standard fitting OD and the other end accepts tube OD for a direct sweat joint. Constructed from domestic copper, this reducer delivers reliable pressure ratings and clean soldering characteristics expected in professional installations.

This reducer is used in residential and light commercial applications where copper tubing must be reduced in diameter — common in HVAC refrigerant line sets, potable water distribution, and hydronic heating systems. Licensed plumbers and HVAC technicians typically install this fitting when joining different-diameter copper runs or when connecting equipment stubs that differ from the field piping size. The domestic copper construction meets typical specification requirements for projects where country-of-origin documentation is required.

Key Features

• Reduces from 5/8-inch fitting end to 3/8-inch copper end in a single fitting
• Fitting x C connection type for direct sweat-solder installation
• Domestic copper construction suitable for projects with material origin requirements
• Compact sweat reducer eliminates the need for an additional coupling and separate reducer combination
• Compatible with standard silver-alloy or lead-free solder for potable and HVAC applications

Compatibility

Designed as an OEM-style sweat fitting for use with standard copper tube and fitting systems requiring a 5/8-inch to 3/8-inch diameter reduction with a Fitting x C connection configuration.

Installation Notes

Installation should be performed by a licensed plumber or certified HVAC technician following applicable local plumbing codes and IFGC or IPC requirements. Shut off and depressurize the system, then purge any refrigerant or water from the line before cutting and fitting. Clean all mating surfaces with emery cloth and apply flux before soldering to ensure a leak-free joint. Do not overheat the fitting during soldering, as excessive heat can compromise the integrity of the copper.

Technical Specifications

• Inlet Size: 5/8 inches
• Outlet Size: 3/8 inches
• Connection Type: Fitting x C (sweat)
• Material: Copper
• Country of Origin: Domestic

Standard Information

• Brand: MUELLER STREAMLINE
• Manufacturer Part Number: W 01321