The resideo NK300S Boiler Feed Combination Valve is a versatile and efficient solution for residential, light commercial, or multi-family buildings with boilers. It combines a testable backflow preventer, pressure-reducing boiler fill valve, strainer, pressure gauge, and two shut-off ball valves into one compact unit. This integration saves time and money on installation and maintenance. The NK300S features test ports on the inlet, middle, and outlet chambers for easy testing. Its fast fill technology with inlet pressure balancing ensures quick and safe refilling.