This residential boiler fill fitting provides a convenient solution to comply with boiler manufacturers' piping requirements. It provides ease of service for expansion tanks and water pressure regulator valves in closed-loop hot water heating systems. Using a unique 3-way ball valve design, it eliminates up to twelve 1/2 inch fittings in a compact package while the one-piece construction eliminates up to eleven threaded joints. It features a unique 3-way ball valve for isolation of water pressure regulator and expansion tank from system pressure. For air charge servicing and maintenance it also has a drain port with integral ball valve for unloading pressure from waterside of expansion tank diaphragm, and a zero to thirty psi pressure gauge for convenient system pressure reference