A.Y. McDonald-Dielectric Unions 72110 - FNPT x SWT-5421-035

The A.Y. McDonald 72110 Dielectric Union (MPN 5421-035) is a premium 1-1/2 inch FNPT × Sweat dielectric union designed to prevent galvanic corrosion when joining copper tubing to threaded steel piping. Manufactured with no-lead brass, galvanized steel components, EPDM/NBR sealing gaskets, and a durable nylon insulating sleeve, this union electrically isolates dissimilar metals to extend the life of plumbing and hydronic piping systems. Rated for 200 PSI at 180°F, the 72110 dielectric union is ideal for water heaters, boilers, commercial plumbing, hydronic heating, and potable water installations requiring corrosion protection and dependable long-term performance.

Cross References

1. A.Y. McDonald — 5421-035
2. A.Y. McDonald — 72110 Dielectric Union
3. A.Y. McDonald — 1-1/2 in FNPT × Sweat Dielectric Union

Usage

The 72110 Dielectric Union is installed wherever copper tubing connects to threaded steel piping. The dielectric insulator prevents electrical continuity between the two metals, eliminating galvanic corrosion and significantly extending piping life. Typical applications include water heaters, hydronic heating systems, boilers, domestic water systems, commercial plumbing, and mechanical rooms. The no-lead brass body makes it suitable for potable water systems, while the galvanized steel threaded end provides a durable threaded connection to steel piping.