Matco-norca dun-0909 Dielectric Union 2-1/2 in Copper Sweat X Fpt

Product Description

The MATCO-NORCA dun-0909 is a 2-1/2 inch dielectric flanged union designed to connect copper sweat piping to female threaded pipe while preventing galvanic corrosion at the joint. The fitting uses a 4-bolt flanged design that allows for clean disassembly without cutting pipe, making it well suited for mechanical rooms, boiler connections, and water service entry points where future service access is required. At 12 pounds, this is a heavy-duty fitting built for demanding plumbing and hydronic heating applications. Licensed plumbers and pipefitters are the primary installers of this type of union.

This dielectric union is intended for installations where copper and ferrous or dissimilar metal piping systems must be joined without creating an electrolytic cell. Common application scenarios include connections at water heaters, boilers, and circulator pumps in both residential and commercial plumbing systems. The 2-1/2 inch size makes it appropriate for larger-diameter mains and primary distribution lines rather than branch or fixture supply runs. The flanged configuration with 4 bolts provides a secure, pressure-rated mechanical joint.

Key Features

• Dielectric fitting construction isolates dissimilar metals to prevent galvanic corrosion
• 4-bolt flanged design allows disassembly and reassembly without cutting pipe
• 2-1/2 inch copper sweat inlet connects directly to cleaned and fluxed copper pipe
• Female threaded (FPT) outlet connects to standard male-threaded pipe or fittings
• Heavy construction at 12 pounds suits high-demand commercial and residential installs

Compatibility

Designed as an OEM-style replacement or new-installation flanged dielectric union for 2-1/2 inch copper sweat to female NPT threaded piping systems in plumbing and hydronic heating applications.

Installation Notes

Installation should be performed by a licensed plumber in accordance with applicable local plumbing codes and IPC requirements. Shut off and drain the water supply completely before cutting into any existing piping. Clean and flux copper pipe ends thoroughly before sweating the union inlet, and apply thread sealant to the male threaded connection at the FPT end. Do not over-tighten flange bolts unevenly — follow a cross-pattern sequence to achieve a uniform seal at the gasket face.

Technical Specifications

• Fitting Size: 2-1/2 inches
• Connection Type: Copper Sweat x Female Pipe Thread (FPT)
• Union Type: Dielectric Flanged Union
• Bolt Configuration: 4-Bolt Flange
• Item Weight: 12 pounds

Standard Information

• Brand: MATCO-NORCA
• Manufacturer Part Number: dun-0909