A manifold is a device in a water system used for connecting the supply and return water of various heating pipes. In underfloor heating and air conditioning systems, the material for manifold valves should be brass, while manifold valves for household meter replacement in potable water supply systems are mostly made of PP or PE. Both supply and return water should be equipped with air release valves, and many manifolds also have drain valves. A "Y" type filter should be installed at the front of the water supply. Each branch pipe of the water supply main should have a valve for adjusting the water flow.