The Utica-Dunkirk 550003878 3-Way Valve is a replacement supply block assembly designed for compatible MAC and DCC 115 and 150 gas-fired boiler systems. It directs water flow through the appropriate heating circuit, helping manage water circulation and support proper heat distribution. This valve plays an important role in maintaining efficient boiler operation and consistent heating ... https://www.partshnc.com/550003878-utica-dunkirk-3-way-valve