The Nortec Humidity 2573523-SP Fill Valve is a replacement water-control component designed for compatible Nortec humidification systems. It regulates the incoming water supply to the humidifier, opening when water is required and closing once the appropriate water level is reached. This valve is used with select Nortec NH050, NH075, NH150, and GH100 commercial and industrial humidifi... https://www.partshnc.com/2573523-nortec-humidity-sp-fillvlvnh050-075-150gh100