Category - Boilers
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Ryan Gill, Engineer

31 Jan : Updated 19 Apr ● 6 min read

How to balance your radiators

Nothing is more frustrating than coming home, turning on the central heating and putting your feet up, only to discover that something is wrong with your radiators

If you find that some radiators in your home are staying cold and others warming up, then the heating system may need balancing. 

You needn’t panic, though! An unbalanced heating system is actually a fairly common issue that can affect heating systems of all types. Fortunately, with the correct knowledge and skills, more often than not this issue can be easily rectified. 

This guide explains why it’s important to balance your central heating system, how to identify radiators that are unbalanced, and provides the step-by-step process for how to fix radiators should they need balancing.

Why do you need to balance your radiators?

When radiators become unbalanced, it means they’re not all heating up at the same time and to the same temperatures. Nine times out of ten, this is caused by your boiler’s water flow and occurs when hot water is being unevenly distributed around your home.

It sounds simple but, in practice, it’s a pretty annoying issue. Some of your home’s radiators might be screaming hot, turning your sitting room into a sauna, whilst others will have cold spots meaning they won’t be able to provide enough warmth for you to relax comfortably. On top of this, the rate at which your radiators heat up will differ. You might find that, after turning your central heating on to its highest setting, the radiators in your bathroom heat up almost instantly, whilst those in your lounge or bedroom take far longer.

The way to fix these issues and restore your home’s temperature to one that Goldilocks would approve of (not too hot, not too cold, just right), you need to balance your radiators. 

engineer working on a radiator

How to tell if your radiators need balancing

Don’t worry, you won’t need an expert opinion to know whether your radiators are unbalanced or not. 

You can perform simple temperature checks yourself by monitoring the rate at which your radiators are heating up and noting whether some get hotter quicker than others. 

You can also check for any cold spots across the surface of your radiators by placing your palm on each corner in turn. If one area feels cooler to the touch than the rest, it’s highly likely that your radiators need balancing.

How to balance your radiators

In order to successfully balance your radiators, you’ll need the following items:

  • A digital thermometer
  • Your radiator bleed key
  • Your radiator lockshield valve key
  • An adjustable spanner
  • Something to make a note of each radiator’s temperature (a pen and paper or your smartphone)

*Note that the amount of time it takes to balance an entire central heating system will depend on how many radiators it has; the more radiators, the more time you’ll need to set aside to complete the job properly!

How to balance your radiators

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1. Turn off your heating

It’s important to start with a completely cool heating system to ensure accuracy.

2. Open all lock shield radiator valves

Next, open the radiator valves on the radiators that are unbalanced. The valves are located at the bottom left or right-hand corner of your radiator and you’ll need to turn them anti-clockwise as far as they’ll go. 

If the valves haven’t been opened in a while, they might be a little stiff. If this is the case, blow the dust off your toolbox, dig out a spanner, and use it to rotate the valve a quarter of a turn before continuing by hand. 

The same applies to lockshield valves, although you’ll need to remove the plastic cap first before attempting to open the valve. Once all the valves have been opened, you can then turn your central heating back on. 

3. Note if some radiators are heating up more that others

Once your radiator valves are opened up, you’ll need to monitor which radiators heat up first, and if any are not heating up/not getting as hot as others. 

It is common that the radiators closest to the heat source (i.e. the boiler) will heat up faster than radiators further away. 

4. Allow your heating to cool down

Allowing the heating system to cool down before rebalancing radiators is crucial for safety and accuracy. If this system is too hot, it can lead to inaccurate readings, potential leaks and damage. Cooling down ensures precise adjustments and even heat distribution.

5. Adjust the fastest radiator

Return to the radiator you identified from step 3 as the one that heated up the fastest. Next, close the lockshield valve completely and then reopen it slightly (about a quarter of a turn).

Once the radiator has started to heat up, you'll need to take some measurements with your thermometer. First, record the temperature of the pipe immediately next to the lockshield valve, then record the temperature of the pipe on the opposite side of the radiator (usually next to the thermostatic valve).

In order for a radiator to be balanced properly, there must be a 12°C temperature difference between either side. To achieve this, you’ll need to open the lockshield valve very gradually until the difference between the two temperature readings is exactly 12 degrees.

6. Repeat for other radiators

Armed with your digital thermometer, repeat this process of opening the lockshield valve and adjusting as required for the remaining radiators in your home. Do this until all the radiators are back to working order and measure a difference of 12°C between each pipe.

Check that your balancing efforts have been successful by going around your house or flat and making sure that all the radiators are heating up at the same rate and to the same level.

Should you bleed or balance your radiators?

Don’t worry! No radiators were harmed in the writing of this blog post. 

Whether it’s in the context of a property we rent or own, bleeding a radiator is something we’ve probably all heard of, if not attempted, at some point or another. But what’s the difference between bleeding and balancing a radiator? And how do you know if you should do one or the other?

When a singular radiator in your home has cold spots at the top, bleeding it is a good idea.  It could be an isolated issue with that particular radiator due to air being trapped inside. 
Balancing the radiators needs to be done when you have issues with radiators getting a poor flow rate of water going through them, this will result in poor radiator performance. Whilst it will take a little longer to perform a proper balancing of your home’s radiator system, it’s definitely recommended if the issues are caused by your central heating’s water flow rate and are affecting your entire home.

How to bleed your radiators

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When is it time for a new boiler?

If you’ve gone through our steps and are still having problems, then there may be a blockage in your system. In which case, you’ll need a professional to power flush out your system and advise on the best course of action. Or you may need a new boiler

For any boiler-related questions, why not drop us a message on our live chat? You’ll get an instant reply from one of our in-house experts. From central heating to boiler replacements, they know their stuff and are more than happy to help.

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