How to bleed a radiator

How to bleed a radiator

How to bleed a radiator

Radiators are an essential part of most people’s homes, providing us with warmth during the colder months. However, many people still have issues when it comes to looking after and maintaining their radiators – more specifically, bleeding their radiators. To help you with this, we’ve put together a quick and easy guide for how to bleed your radiators:


What is bleeding a radiator?

Bleeding a radiator is the process of letting out air that has been trapped (this is common in unvented heating systems). The trapped air stops water from heating all of your radiators, causing them to have cold spots.


How to check if your radiator needs bleeding

A good way to check for this is to touch your radiator on the top and indicate whether it is colder than the bottom. If it is, this shows the radiator isn’t efficiently working. You may also want to listen out for gurgling or clanking sounds.


What you will need to bleed a radiator

For most radiators, you will only need two simple pieces of equipment:

A radiator key: If you don’t know a radiator key, they can easily be found at any DIY or supplies shop.

A cloth or rag: You’ll need a cloth or rag to catch any water that comes out of the radiator.


Steps for how to bleed a radiator:

  • Make sure your heating is turned off. If it’s not, there is a high possibility that the radiator will be too hot to touch, and hot water could potentially spray out of the radiator.


  • Attach the radiator key to the groove in the valve (as shown in the image) and turn it anticlockwise. You should then hear a hissing noise which indicates that the trapped air is escaping.


  • Once the hissing stops, retighten the valve. Make sure you do this as quickly as possible to stop too much water from escaping. Be sure to use a rag to catch any water


  • The easiest step of the process… Turn your heating back on


  • Once completed be sure to check the pressure of your boiler as bleeding the radiator can cause the pressure to lower. If the pressure is too low, you will need to top it up.


  • Finally, check the radiator is now heating up properly. If the heat is evenly distributed throughout the radiator, then you have successfully bled your radiator.


Helpful Tips

We hoped the step-by-step guide helpful for you. As much as bleeding a radiator may look simple on paper, there a few things you can do to help keep your home clean when doing the process.

Prepare the area before bleeding: You might want to place rags or kitchen rolls underneath the radiator before you begin the process as radiator water can be discoloured. That’s the last thing anyone wants on their floor!

Turning your heating on You of course want your heating to be turned off when you carry out the bleeding process, however, in advance, you may want to turn your heating on as this can push unwanted air out due to the build-up of pressure.


If you have any further issues with your radiators or any other form of issues with your household heating, then please get in contact with us on 0800 043 0458 and one of our skilled engineers will be with you as soon as possible.