The Resideo QVU8143A3231 N/C Rebuild Kit is a replacement service kit designed for 1/2-inch to 1-inch VU53 normally closed fan coil valves. It restores valve operation by replacing internal components, including the valve stem and sealing mechanism, to regulate hot or chilled water flow through hydronic HVAC systems. Suitable for commercial fan coil units and closed-loop heating and c... https://www.partshnc.com/qvu8143a3231-resideo-nc-vu53-12-1-rebuild-kit