How to bleed a radiator

Bleeding a radiator can be great for the efficiency and warmth of your home. It is a very simple process that can be learnt in just a few minutes by reading this blog post. 

How do I bleed my radiators?

Bleeding a radiator is all about releasing trapped air and will help your boiler to become much more efficient. To find out how to bleed your radiators, keep reading...

Spot the problem

Before you think about bleeding your radiators you need to have a reason to do so. All systems will occasionally need bleeding but some signs to look out for include cold spots, or your radiators taking a long time to heat up.

Check all radiators

If you have noticed a problem with one, it is a good idea to fire up your system and check the others too. See how long they take to warm up and feel for any inconsistencies with temperature. If you find any other problems, you should bleed these radiators too.

Turn the central heating off

You must switch off your heating, or the job will become a lot messier than it needs to be. If the heating is left on, you will be left with a puddle of water when you open the valve.

Release the trapped air

This is the main step with bleeding your radiators. You need a radiator key (available cheaply online or in any DIY shop) and an old rag or tea towel. Fit the key to the valve at the top of the radiator, using the rag to catch any drips and protect your hands. When the key is fitted, begin twisting it anti-clockwise to let the air escape.

Close the valve

When the valve is open, you will be able to hear the air escaping. When the noise becomes less, water will be moving towards the hole. When all the air has gone and you feel the water coming, close the valve quickly to reduce the amount of water that pours out.

Check the pressure

When the radiator has been bled, you need to check the pressure gauge on your boiler. If the pressure is now too low, you need to top it up. Adjust it using the filling loop and the instructions from your manufacturer.

Need a boiler specialist in West Sussex?

Our boiler services are based in  Rustington, West Sussex- but we also cover Angmering, East Preston, Ferring, Littlehampton, Arundel, Worthing and the rest of the South Coast, including Brighton and Chichester. Our team of gas engineers are experts in their field and have years of training and experience, so why look anywhere else? For the best in the business, look no further than Shoreline. To get in touch with our team today, give us a call on 01903 863224 / 07584 093260 / 01243 884222, check out the contact form on our website, or send us an email at We hope this blog post has helped you to bleed your own boilers at home!