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How to bleed your radiators

How to bleed your radiators

Oct 17, 2017

Bleeding your radiator releases the air trapped inside them. It’s important to do this to ensure your central heating system is warming your home properly. If there are air bubbles trapped inside, it will prevent hot water from circulating effectively, so radiators aren't as hot as they should be, meaning they will take longer to warm your home.

It’s easy to bleed your radiators yourself. To help you with this, we have put together a step by step process of how to do this.

Step 1: Turn your central heating system on

It’s important to turn your heating on to allow all your radiators to heat up.

Step 2: Identify which radiators need bleeding

Check each radiator to see if all parts of it are warming up. Any cool spots (particularly towards the top) indicate that there could be air trapped inside the radiator that will need to bleed out.

Step 3: Bleed the radiator

For this, you will require a radiator key or a flat-blade screwdriver. If you don’t have these, you’ll easily be able to pick them up from your local hardware store.

Switch off your central heating system.

At the top of one end of the radiator, there will be a valve. Attach the radiator key to the square part in the centre, or put the end of the screwdriver into the groove. Hold the key/screwdriver with a cloth, and have another cloth ready to catch any drops of water. Slowly turn the radiator key anti-clockwise – if gas is coming out, you’ll hear a hissing sound.

Once all the gas has been removed, liquid will begin to come out, so the valve will need to be quickly closed.

Step 4: Check the pressure of the boiler

You can check the pressure by looking at the gauge on your boiler. If the pressure is too low, you will need to top it up. You do this using the lever or tap on your boiler known as the filling loop.

Step 5: Check if its worked

Check if your efforts have been successful by switching your central heating back on and letting all the radiators heat up. Check them again for any cool spots.

And that’s it, you’ve successfully bled your radiators!

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