GRUNDFOS - FLANGE KITS FOR UNION MOUNTED PUMPS (Models, UPS15-35SUC/LC/DT, UPS15-55SUC/LC/DT) 3/4" bronze union sweat fitting set - 529911

The Grundfos 529911 Bronze Union Sweat Fitting Set provides a durable connection between compatible Grundfos union-mounted circulator pumps and 3/4 in copper piping. Manufactured from corrosion-resistant bronze, each adapter features a copper sweat connection on the piping side and a GU125 union connection on the pump side. The union design allows the circulator to be removed or replaced without cutting the connected copper tubing. Supplied with two bronze adapters, two union nuts, and two sealing gaskets, this genuine Grundfos accessory is designed for hot-water recirculation, hydronic heating, and compatible potable-water circulation systems using selected UP and UPS Series pumps.

Cross References

• Grundfos — 529911: 3/4 in sweat × GU125 bronze union fitting set
• Grundfos — 529913: 1/2 in sweat × GU125 bronze union fitting set
• Grundfos — 529912: 3/4 in NPT × GU125 bronze union fitting set

Usage

The Grundfos 529911 fitting set is installed between 3/4 in copper piping and a compatible Grundfos union-mounted circulator. Each bronze adapter is soldered onto the copper tube before the pump is connected. The supplied gaskets are positioned at the GU125 union faces, and the union nuts secure the circulator between the two adapters. This configuration is commonly used in domestic hot-water recirculation, boiler circulation, radiant heating, and compatible HVAC systems. The unions allow the pump to be disconnected later without cutting or resoldering the system piping; however, this set does not contain built-in isolation valves.