Balancing Radiators: A step-by-step guide

30 March 2021
Balancing Radiators: A step-by-step guide
Adjusting a radiator valve with a spanner and pair of grips

If you're finding that some radiators in your home aren't getting hot as quickly as others, it might be that your radiators need balancing. In this article we'll run you through the process of how to balance your radiators so that heat is distributed evenly around your home again.

  • Balancing vs bleeding
  • Turn off your central heating
  • Bleed your radiators
  • Go to radiator number 1
  • Close then open the lockshield valve
  • Repeat on all radiators

Balancing vs Bleeding

If your radiators are not balanced, it means that hot water is not circulating around your central heating system evenly. A classic sign is a radiator nearest your boiler getting hot while radiators further away only get lukewarm or even remain cold.

When a radiator gets air trapped inside it, you need to 'bleed' (or let out) this air using a radiator bleed key. The most common symptom of a radiator that needs bleeding is when it feels cold at the top and hot at the bottom. Effectively, the trapped air at the top of the radiator is stopping the hot water filling up the whole chamber of the radiator, hence the difference in temperature between the top and the bottom.

Bleeding radiators is one of the easiest heating-related jobs you can do and it can be included in the balancing process.

1. Turn off your central heating

Before you do anything, make sure that your heating system is turned off and you give your radiators a chance to cool down. Scalding yourself due to hot rads is not a good way to start so take this step seriously.

2. Bleed your radiators

If you identified any radiators that were only getting hot at the bottom, then this would be a great time to bleed any air out and get this issue resolved.

3. Go to radiator number 1

This will normally be the radiator that gets hottest the quickest. It's often the closest to the boiler and will quite often be upstairs, if you're in a two-storey home. This is likely to be the radiator that is responsible for pinching all the hot water and sending it back to the boiler rather than to the rest of the radiators.

4. Close then open the lockshield valve

On radiator number 1, go to the lockshield valve. This is the valve that usually has a pointed plastic cover on it and looks like it doesn't do much.

Take a flat head screwdriver (or a pair of grips) and fully close the valve by turning it clockwise as far as it will go. Then open the lockshield valve (anti-clockwise) by a quarter or half turn.

5. Repeat this process on all radiators

You might find that just closing and opening the lockshield valve on radiator number 1, described above, is enough to solve the problem and get all your radiators heating up equally.

After dealing with the first radiator, you could switch your central heating system on and find out. However, just to be extra sure you should go through this process on all of your radiators and then switch your heating on.

You should find that this has solved the problem and all radiators are getting up to temperature exactly as they should be. If not, them it's time to call in a professional.


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