A zone valve regulates water flow through closed heating and cooling systems. These systems are divided into separate zones throughout a house where temperatures may be individually controlled due to the valves mounted on each zone's piping.
Zone valves supply heat if they are turned on in specific areas and are often electrically powered with a motor connected to a rotary switch. They are connected to thermostats located within the individual zones and begin to operate once the thermostats signal a need for heat. The valves may malfunction if the thermostats are not working properly and must operate with their covers on to accurately regulate the temperature.