How to Bleed a Radiator – 4 Simple Steps

As the temperatures in Gloucestershire drop to sub-zero, WCPH explain 4 easy steps to bleed your radiators. Please follow all manufacturing safety guidelines before attempting this tutorial and if you have any questions or concerns please contact us by clicking here.


A household task that sounds far more dramatic than it is – bleeding your radiators regularly can improve the efficiency of your whole heating system, meaning a warming home and cheaper bills. Radiators can develop cold patches when air becomes trapped in them, and bleeding them allows that air to escape. Follow the simple step-by-step guide below to ensure you’re getting the most out of your heating system this winter.

Step One: Locating the problem

Most radiators will need bleeding at some point, however the most obvious symptoms that show your radiator requires attention are:

  • It takes an abnormally long amount of time to heat up
  • It is colder at the top than the bottom

The best way to diagnose which radiators need bleeding is to turn your heating on, and feel the radiators for inconsistencies in temperature.


Step Two: Releasing the air

It is vital you turn off your heating before actually bleeding the radiator, to avoid injuring yourself and leaking water over the floor. Once you have located the radiator that needs bleeding, attach your radiator key to the square in the centre of your radiator’s valve. You can do the same thing with the end of a screwdriver. Holding the screwdriver or key with a cloth, and using another cloth to catch any drips, slowly turn it anticlockwise, and listen for the hissing noise of air escaping.

It is vital you turn off your heating before actually bleeding the radiator.


Step Three: Shutting the valve

Once you can no longer hear air escaping, water will push through where the air has been and start to drip out. As soon as this happens, close the valve by turning it firmly clockwise.

Step Four: Check the pressure

Bleeding radiators can affect pressure, after you have completed the previous steps it is a good idea to check the pressure gauge on your boiler. If the pressure is too low, you will need to top up. You can do this using the filling loop and following instructions from your boiler manufacturer. It is also advisable to turn your heating on again afterwards to check your efforts have been successful.

Good luck! (It’s not as bad as it sounds…)

West Country Plumbing and Heating only offer the above as an informative guide and cannot be held responsible for any damage or injuries caused. For more information about safety, please contact your heating appliance manufacturer.

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