High Quality Content by WIKIPEDIA articles! A zone valve is a specific type of valve used to control the flow of water or steam in a hydronic heating or cooling system.IN the interest of improving efficiency and occupant comfort, such systems are commonly divided up into multiple zones. FOr example, in a house, the main floor may be served by one heating zone while the upstairs bedrooms are served by another. IN this way, the heat can be directed principally to the main floor during the day and principally to the bedrooms at night, allowing the unoccupied areas to cool down.ZOne valves as used in home hydronic systems are usually electrically powered. IN large commercial installations, vacuum or compressed air may be used instead. IN either case, the motor is usually connected to the water valve via a mechanical coupling.FOr electrical zone valves, the motor is often a small shaded-pole synchronous motor combined with a rotary switch that can disconnect the motor at either of the two stopping points ("valve open" or "valve closed").