Adding zones to your boiler could be an excellent idea, and one that is beneficial for many reasons.

Zoning allows you to have more control over the temperature of various rooms in your home and could even make your heating system more efficient. For example, you could choose to zone upstairs from downstairs so that your heating comes on in the morning to heat the lower rooms of your house. Then, in the evening, the heating will only heat the bedroom.

You could add further zones that allow your living room to be heated but not your kitchen. Kitchens tend to be warmer rooms because of the appliances they contain, such as cookers and tumble dryers. Such appliances increase the room’s temperature, so heating this room using your boiler could be a waste of money and energy. Zoning could be beneficial in this circumstance.

Below, we’ve identified how you can zone your heating system, how a zone valve works and how you can identify a faulty valve. 

Can I zone my heating system?

Zoning your heating system cannot be done directly from your boiler. Instead, you will need to purchase some external devices, such as zone valves, and have these installed by a suitably qualified engineer. Although you will have to pay for these additional parts, you could increase the efficiency of your home and therefore save money on your heating bills. It can also help reduce your home’s environmental footprint by cutting CO2 emissions.

If you’re unsure whether a zone valve can be added to your boiler system, you could contact the manufacturer for an answer. 

What is a zone valve?

A zone valve is a special valve that regulates the flow of water through a heating system. When the valve is closed, it will completely block off the flow of water to your radiators so that they stay cold. When it is open, the hot water is allowed to flow through to heat up your home.

A zone valve will be connected to a thermostat, which allows it to detect when the room temperature has reached the correct level. When this happens, the valve will close and prevent any more hot water from flowing through the radiators. As the room temperature drops, the valve can open again.

There are different types of zone valves that work in different ways. Some may cost more than others, so have a think about your budget and what you’re willing to spend on zoning your home. Two port zone valves will typically open or close off water flow to a heating zone. Three port mixing valves achieve the same, but can additionally adjust the water flow temperature to the optimum required at that time.

The majority of zone valves will also contain a manual lever which can also be useful when it comes to testing your system. Zone valves can become faulty over time, and having a manual lever means you’ll be able to test the valve to see if it’s working. Read on to find out more about faulty valves and how to determine if there’s a problem.

How to check if a zone valve is working

Ensuring that your zone valves continue to work correctly is important. A faulty valve that is stuck in the ‘open’ position will allow hot water to flow through your radiators whenever the heating is on, instead of stopping the flow when not required. If this room isn’t being used, then you’re wasting both money and energy on heating it.

If you think that your zoning circuit isn’t working, there could be a few reasons for this.

The most common issue is that the valve itself has become stuck. As already mentioned, it could either stick in the ‘open’ or ‘closed’ position. A suitably qualified heating engineer may be able to fix it or the valve may need replacing.

A faulty thermostat could also be causing problems. If the thermostat is reading an incorrect temperature, it could prevent the valve from heating the room as it detects that the room is already warm enough. However, it could also cause the opposite problem and begin to overheat the room/zone. In this instance, it’s likely that the thermostat will need replacing by a Gas Safe registered engineer.

Finally, the zone valve could have a leak. The valve will be fitted with a rubber seal so that when it’s closed, no water is allowed through the pipes. This rubber seal can degrade over time and allow some water through. In some cases, a new seal could be fitted. However, in more serious cases, the valve may need replacing. You should get advice from your heating engineer about which route is the best to take.

Once you’ve determined that you may have a problem with a zone valve, it can be hard to pinpoint exactly what the issue is. In order to find a faulty valve that is stuck in the ‘closed’ position, you can try the following.

Turn all the radiator thermostat valves in one zone up to full (usually the number five). This means that every radiator valve in that zone should now be allowing hot water through. Wait for 30 minutes, then check each of your radiators by hand. They should all be hot.

  1. If all radiators remain cold, then the zone valve may be stuck closed.
  2. If individual radiators remain cold or lukewarm, then the fault will probably be with the radiator valve.
  3. If you think that a zone valve is stuck in the ‘open’ position, you can perform the opposite test. Turn all the radiator thermostats on the radiators down to zero (or the snowflake symbol). Wait for around 30 minutes and then check each to see which are cold.
  4. If all radiators remain warm, then the fault will most likely be a stuck open zone valve.
  5. If only one or two individual radiators remain warm, the radiator valve or valves should be checked.
  6. If you require a new valve, you’ll need to organise for a suitably qualified heating engineer to come and fit one for you.

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