GRUNDFOS - FLANGE KITS FOR UNION MOUNTED PUMPS (Models, UPS15-35SUC/LC/DT, UPS15-55SUC/LC/DT) 3/4" bronze union isolation valve set (threaded) - 519852

The Grundfos 519852 Bronze Union Isolation Valve Set provides a compact, service-friendly connection for compatible Grundfos union-mounted circulator pumps. Each valve features a 3/4 in female NPT threaded pipe connection and a GU125 union pump connection. Built-in shut-off valves allow the circulator to be isolated for inspection, maintenance, or replacement without draining the complete hot-water circulation system. Durable bronze construction provides corrosion resistance for potable-water and compatible circulation applications. Supplied as a complete pair with union nuts, sealing gaskets, and valve adapters, this genuine Grundfos accessory supports reliable installation of selected UPS15-35 and UPS15-55 union-mounted pumps.

Cross References

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

Usage

The Grundfos 519852 set is installed between the system piping and a compatible union-mounted circulator. The 3/4 in female NPT ends connect to the piping, while the GU125 union nuts and gaskets connect the valves to the pump. During normal operation, both isolation valves remain fully open. When servicing or replacing the circulator, the valves are closed to isolate the pump and reduce water loss. This arrangement eliminates the need to cut piping and greatly reduces the need to drain the complete domestic hot-water recirculation loop. It is commonly used with Grundfos UP and UPS circulators equipped with GU125 union connections.