A manifold is a device in a water system used to connect the supply and return water for various heating pipes. In underfloor heating and air conditioning systems, manifolds should be made of brass. Manifolds for household meter replacement in potable water supply systems are often made of PP or PE materials. Both supply and return lines should have air vent valves, and many manifolds also have drain valves. A "Y" type filter should be installed at the front of the supply line. Each branch of the supply pipeline should be equipped with a valve to regulate the water volume.