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06 June 2022

How To Bleed Your Radiator Yourself

If your radiators aren’t heating up properly, have cold spots, or are completely cold despite your heating being on one of the things you might want to try is to bleed them. Bleeding your radiator is the act of removing trapped air that has built up inside your radiators.This trapped air can affect the efficiency of your central heating. It is very simple and easy to bleed your radiator yourself, all you will need is a radiator key and a cloth/tea towel to catch any water.

Children playing in front of a perfectly heating radiator after their parent learnt how to bleed the radiator
If your radiators aren't heating properly you might need to bleed them

Why would you need to bleed your radiator yourself?

If you’ve noticed that your radiators are cold at the top and hot at the bottom, or any of the other things I have mentioned, it probably means that there’s air trapped inside the system. The air is preventing water from circulating your radiators, therefore the room will not heat up as quickly and your energy bills will be higher due to inefficient central heating. 

Another reason you may wish to bleed your radiator yourself is because they’re making loud banging, gurgling, or clanking noises. This is again due to trapped air, and can be easily fixed.

Energy suppliers recommend bleeding your radiators at least once a year, even if they’re fully functional. Don’t worry though, because this is something that anyone can do, and it will only take 5 minutes of your time.

How to bleed a radiator yourself

Firstly, you’ll need a radiator key. These are specially shaped keys that open and shut off the valve at the top of radiators. Don’t worry if you can’t find yours, they’re easy to find in hardware shops, or you can purchase them cheaply online. 

If you want to bleed your radiator yourself, safety is paramount, therefore make sure you have turned your heating off at the boiler and allowed the system to cool down completely. If you do not do this, you run the risk of hot water spraying out of the radiator valve and burning you. You may also find that your radiator will be too hot to touch. 

Next, attach the radiator key to the square valve at the top of your radiator. To bleed the radiator yourself, secure the key and turn it slowly in an anticlockwise motion. As you do this, you should hear a hissing sound. This is the sound of the air escaping through the valve. 

To continue bleeding the radiator yourself, allow the trapped air to escape and retighten the valve as soon as the hissing stops and a steady trickle of water starts to come out. You will want to tighten the valve as quickly as possible to avoid too much water escaping. This is where your cloth or tea towel will come in handy as you’ll be able to soak up any water that does manage to escape, and avoid getting any on your carpet or walls. 

Repeat the process on all radiators in your house, it doesn't matter the order you bleed the radiators in, but it is recommended to do them all at the same time. 

Now it’s time to turn your heating back on

After you have tightened the valve on your radiator, it’s time to go back to your boiler and turn your central heating system back on. After you have bled the radiator, you will notice a drop in pressure as shown by the gauge on your boiler. If it is too low (the gauge might be pointing to red instead of green or on digital boilers you might have an error message) you will need to let more water into your boiler to increase the pressure. The handbook that came with your boiler when it was installed will provide details on how to build pressure safely and note what the optimal pressure should be. If you can't find the manual then check the manufacturers website, they often have useful guides. Some boilers need a plumber to restore the pressure.

Check your radiators are now heating up properly

Once your heating is back on, you should notice that there are no more cold spots on your radiators. They will be heating up properly and your central heating system will now be working efficiently again - saving you money and keeping you warm! 

Congratulations, you now know how to bleed a radiator yourself!

A few hours after you’ve bled your radiators, it’s a good idea to go around each one to ensure the valves aren’t leaking and check to see if they’re still heating up properly. If you find there are still some areas that are cold, you may have other issues with your central heating system, such as sludge in your radiators or an air leakage. If this is the case, it’s best to call a professional. 

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