NIS renews circulation and pressure control valves, pressure relief and safety valves, constant pressure valves, and extrusion valves. Valves are restored to like-new condition through a cleaning and renewal process that replaces all the wear components and returns the valve to factory settings. All seals and wear parts are replaced using OEM-equivalent parts. Stems are replaced as needed. Each unit is tested to ensure it works properly. NIS designs new seats to improve performance and life.