The Watts S1156F is a 1/2-inch high-capacity boiler feed water pressure regulator designed for use in commercial and residential hydronic heating systems. This valve is engineered to automatically fill the boiler and piping system with water and maintain system pressure at all times. It features a durable bronze body construction with a union solder inlet and NPT threaded outlet connection. Key technical features include a tight-seating check valve to prevent backflow, a stainless steel strainer to protect the valve disc from fouling, and a manual purge lever for fast filling and air purging during initial setup. It has a maximum pressure rating of 100 psi (6.9 bar) and an adjustable reduced pressure range of 10 to 25 psi, factory set at 15 psi. This model is intended for non-potable water applications in boiler feed lines