What is a Zone Valve?

Zone valve is a type of valve that is used to regulate how much water flows through a closed heating or cooling system. Generally, such a system will be divided into zones, covering different parts of your home, to make the system more efficient and economical.

Thus, if your house has a main ground floor with the bedrooms situated on the second floor, each of the floors representing a separate zone, you can make your system provide heat only to the ground floor during the day and just to the second floor during the night (the unsupplied floor being let to cool down). This regulated distribution of heat is possible through the zone valves, which are mounted to the piping for each zone and can shut down or turn on the heat to that zone.

Makeup and Performance of Zone Valves

Most household zone valves currently in use are electrically powered (in rare cases, instead of electricity, vacuum or compressed air can be used). They have a motor attached to the actual valve via a mechanical coupling and are protected by an aluminum cover.

A valve will also have a rotary switch which can disconnect the motor at one of the two stopping points ("open valve" or "closed valve"). Thus, if you apply power to the "open valve" terminal, you will make the motor operate as long as the zone valve is open, whereas if you apply power to the "closed valve" point, you will cause the motor to run until the valve is closed.

Zone valves are connected to thermostats, which are situated in a particular house zone, and begin to function immediately after they receive a signal from the thermostats that heat is needed. A faulty thermostat will not allow the zone valve to operate properly; therefore, have your thermostats checked by a professional on a regular basis.

Zone Valve Defects

There are a number of particularly conspicuous zone valve problems you should be on the lookout for:

  • The zone valve is jammed or stuck. If no water goes to its zone, it is highly possible that a valve has been jammed and in need of professional checkup.
  • the manual lever of the valve is in the “on” position. Every zone valve has a manual lever to turn it on and off, usually located at the bottom of the valve box. If you have just moved into a new house and discovered that the manual lever is set in “on” position, this should indicate that the valve does not operate properly. Otherwise, it would not have needed manual adjustment. This valve is forced to provide heat all the time which is neither efficient as it will soon wear off, nor inexpensive: it will be consuming electricity 24/7. Therefore, set the manual lever in “off” position, and if the valve does not work, consult an electrician.
  • The cover of the zone valve has been removed. Dismounting the valve cover helps it cool down. If your zone valve has its cover taken off, this may indicate that the valve overheats sooner than normal.
  • The zone valve is leaking. A leaky valve should be replaced as soon as it has been detected to avoid bigger damage to the heating system.