Homeowners Professionals

How to balance radiators

Please note this article is designed as a general guide for consumer awareness only. A fully qualified heating engineer will adopt a different and far more technical approach which looks at many other factors to ensure your system is optimally set. Viessmann always recommends you speak to a heating engineer in this instance.

We often take our radiators for granted - they heat up and cool down automatically depending on the programme of your heating system. However, if you find cold spots or discover that one radiator isn’t getting warm at all, you’ll certainly notice the temperature difference in your home.

In some cases, your radiators may need bleeding. This process involves taking air out of the system that could be blocking the hot water from heating a radiator fully. However, if you’ve tried this and you’re still finding issues with one or multiple radiators heating up, it could be that they need balancing instead or that the system might need flushing by a qualified engineer.

What does balancing radiators mean?

When you balance a radiator, you’re adjusting the flow of water in the system. If you have one radiator that is always colder than the others, balancing will allow less hot water into the hottest radiators and more water into the cooler one to make sure it reaches the right temperature. Bleeding, on the other hand, is about removing air from the system. 

When to balance radiators

Put simply, if you notice that some radiators in your property are warmer than others - despite being on the same setting - or if these radiators don’t heat up at the same speed as each other, it’s likely time to balance your central heating system. Cold spots and uneven heating output happens when the hot water produced by your boiler is not distributed evenly. Luckily, if this is indeed the problem, balancing your radiators is a relatively quick and easy process. 

How often should you balance your radiators?

Unless your central heating system has had work done on it - such as a system flushing/cleansing or a boiler/radiator replacement - balancing can be done on a periodical basis. This is to say, you only really need to bleed and potentially balance your radiators if your radiators are heating up at different speeds. However, you will always need to ensure your radiators are balanced after work is done on your central heating system.

Do I need to balance or bleed my radiators?

Although connected, balancing and bleeding radiators are different processes. You may find that you need to do both of these things in order to get your radiators working properly again.

As discussed above, bleeding a radiator involves removing any trapped air from your central heating system that may be blocking hot water from heating a radiator. If you are experiencing cold patches in certain radiators, or some radiators performing more effectively than others, bleeding should be your first thought. Here’s our video guide on how to bleed a radiator.

If, however, bleeding your radiators does not solve the issue of certain radiators heating up more efficiently than others, you will likely have to balance the system instead. We explain how this can be done below. 

How to balance a radiator

Below, you can find all the steps you need to successfully balance your heating system. Before following these instructions, you should allow the radiators to cool down completely and bleed them using a radiator bleeding key.

Is there a tool for balancing radiators?

Although there are not any unique tools required for balancing radiators, there are a number of common tools needed to make this job possible. These can all be found in a typical toolbox and, if you don’t already own them, can be bought relatively inexpensively from any DIY shop.

These tool include: 

  • Standard radiator bleeding key

  • Screwdrivers (both Phillips and flathead)

  • Lockshield valves key (or an adjustable spanner)

Important: Please note that this work is usually done by an engineer as water leaks can occur when adjusting radiator valves.

Step 1: Locate the lockshield valve on each of your radiators. These will normally be located on the opposite side to the thermostatic radiator valves (TRVs) that are used to control the heat output. Remove the lockshield valve caps from all radiators.

Step 2: Now that the valve caps have been removed, you should be able to open and close the valve to each radiator. Open the valves by turning them to the left. Repeat this for all of your radiators.

Step 3: Once every valve is open, turn your heating on. You need to monitor which radiators heat up fastest. It may be easier to have a family member or friend to help you with this task, otherwise you’ll be running around the house trying to determine what each radiator is doing. Radiators nearest the boiler will probably get warm first, so take this into account.

Step 4: Turn the heating off again and wait for everything to cool down. You should now have a list of which radiators are getting hottest the fastest and those that maybe aren’t getting hot at all or have cold spots. You’re doing this to balance the flow of water running through the system. Turn the heating back on.

Step 5: Go to the radiator that heated up the fastest and close the valve that you opened in Step 2 by turning clockwise. Once it’s fully shut, open it slightly using your lockshield valve key. Now repeat and move to each radiator, the furthest away radiators may need to be opened more than those closest to the boiler.

If you’ve followed all of these steps, what you have done is restricted the hot water flow to radiators that are the warmest and allowed more water into those that need it more. Your radiators should all be balanced and you can enjoy your warm home.

How long does it take to balance radiators

Unlike the bleeding process, which typically only takes a few minutes to complete, balancing radiators can take a couple of hours to complete from start to finish. That being said, some of this time will be spent simply waiting for your radiators to heat up and cool down. 

Does balancing radiators save money?

Balancing your radiators can save you money on your heating bills. This is because you’re giving the correct balance to each radiator to ensure your boiler doesn’t keep cycling on and off and giving your system a nice smooth flow. If you are looking to save even more money on your heating, try turning your thermostat down by one degree.

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