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The AY MCDONALD 5423-276 is a 1-inch lead-free brass insert adapter designed to transition PEX-A tubing to a male sweat (solder) copper connection. This fitting allows a licensed plumber to bridge PEX-A flexible pipe runs to copper sweat fittings without additional adapters or specialty tools beyond standard PEX expansion and sweat equipment. The lead-free brass construction meets potable water requirements, making it appropriate for domestic water supply systems in residential and light commercial applications. Its insert-style end grips the interior of the PEX-A tube after expansion, creating a reliable, watertight mechanical connection.
This adapter is used where PEX-A distribution lines must terminate at or connect to copper sweat assemblies. Common install scenarios include mixing manifold transitions, water heater connections, fixture supply rough-ins, and retrofit work where existing copper lines are being extended with PEX-A. The 1-inch size suits main distribution runs in residential systems and branch mains in small commercial builds. It is intended for use with PEX-A tubing only, not PEX-B or PEX-C, as the expansion method is specific to PEX-A material memory properties.
Designed as an OEM-style transition fitting for 1-inch PEX-A tubing systems connecting to copper sweat piping assemblies in residential and light commercial potable water applications.
Installation should be performed by a licensed plumber in accordance with local plumbing codes and the International Plumbing Code (IPC). Shut off the water supply and depressurize the line before beginning work. Use a calibrated PEX-A expansion tool sized for 1-inch tubing to expand the PEX-A end before seating the insert; allow the tubing to recover fully around the fitting. Complete all sweat soldering on the copper end before connecting to the PEX-A side to avoid heat damage to the tubing.
We pulled together the parts most installs need for this unit, plus a few add-ons worth a look. Check what you need — nothing here blocks checkout.
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