The Bock F5 valve plate assembly is a part of a water heating system. It is used to control the flow of hot water throughout the system. The assembly consists of a valve plate, a spring, and a handle, which all work together to regulate the flow of water. The valve plate is made of cast iron and is designed to open and close when the handle is turned. The spring helps to keep the valve plate in the closed position when it is not in use. The handle is used to open and close the valve plate, and the handle can be locked in place when the plate is in the closed position.