BASI Guide: how to bleed your radiators


Bleeding your radiators is necessary for keeping your heating running efficiently. You should check your radiators at least once a year to see if they need bleeding.

A simple process, bleeding your radiators releases the build-up of air in your system. Air trapped in your radiators causes cold spots which make your central heating less efficient – costing you more.

Not sure know how to bleed your radiators? Don’t worry!

We’ve put together this step by step guide to talk you through it.

  1. Start by turning you heating on

When all your radiators have warmed up – paying attention not to burn yourself – gently test the temperature all over the surface of each radiator to check for cold patches.

  1. Pinpoint which radiators need to be bled

Any radiators that have cold patches will need to be bled, so note down a list as you are testing.

  1. Now turn off your heating

Wait for your radiators to cool down so you can begin handling them.

  1. Find the valve at the top of your radiator

Position a cloth just under the value in order to catch any drips, then using a radiator key or a flat blade screwdriver, begin loosening the valve.

Any released air will be indicated by a hissing or whistling noise.  Keeping going until all air has been released.

  1. Be prepared to reseal the valve quickly

Once all the air is gone, water will begin pouring or spurting out of the radiator, so be prepared to quickly retighten the valve as soon as this happens.

  1. Check your pressure

Once you have successfully bled all your radiators, check the water pressure. It should be between 1 and 2 but if it’s any lower, you can adjust it using the pressure valve.

Having trouble bleeding your radiators?

Or want some professional advice? Arrange a central heating service and one of our friendly engineers will be able to come at a time that is convenient for you to check everything is working as it should be.

It won’t take more than a couple of hours and a standard service with BASI costs just £65. Get in touch now to book your boiler service.

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