GRUNDFOS - FLANGE KITS FOR UNION MOUNTED PUMPS (Models, UPS15-35SUC/LC/DT, UPS15-55SUC/LC/DT) 1/2" bronze union isolation valve set (threaded) - 519850

The Grundfos 519850 Bronze Union Isolation Valve Set provides a compact, service-friendly connection for compatible Grundfos union-mounted circulator pumps. Each set features 1/2 in female NPT threaded pipe connections and GU125 union connections, allowing the pump to be isolated and removed without draining the complete domestic hot water or hydronic circulation system. Durable bronze construction offers dependable corrosion resistance, while the integrated shut-off valves simplify pump installation, replacement, and routine maintenance. Supplied with two valve adapters, union nuts, and sealing gaskets, this genuine Grundfos accessory is ideal for hot water recirculation, boiler circulation, and compatible residential or light-commercial pumping applications.

Cross References

• Grundfos — 519850: 1/2 in NPT × GU125 union bronze isolation valve set
• Grundfos — 519852: 3/4 in NPT × GU125 union bronze isolation valve set
• Grundfos — 519851: 3/4 in compression × GU125 union fitting set

Usage

The Grundfos 519850 set is installed between the system piping and a compatible union-mounted circulator. The 1/2 in female NPT ends connect to threaded piping, while the union nuts and gaskets secure the valves to the pump’s GU125 union connections. Closing both built-in isolation valves separates the circulator from the piping system, allowing the pump to be removed, replaced, or serviced with significantly less water loss and without draining the complete loop. It is commonly used on domestic hot water recirculation systems and other compatible circulation applications requiring accessible pump isolation.