How to Bleed a Radiator

Is your radiator not very hot anymore? It may need bleeding.

You don’t need a professional, you can bleed a radiator yourself at home. We’ve put together a step by step guide to help you out.

Before we start, you need to check that the reason you’re having trouble with your heater is because it definitely needs bleeding and not a problem that may need professional expertise.

The most common signs include; gurgling noises, taking longer to heat than usual, the top of the heater still feeling cooler than the rest of the radiator or even the whole heater feeling cold even though the heating is on.

Radiators usually only need bleeding once a year.

Once you’re sure your radiator needs bleeding, here’s the best way to do it:


1. Turn on your radiator
Allow your radiator to heat up and push out any unwanted air and built pressure. This step also helps to identify which of your heaters need bleeding by looking for the signs we outlined above.


2. Turn off the heating
Once you’ve identified which radiators you need to bleed, you need to make sure the heating is turned off in order to bleed them. This is because it may be too hot to touch, and you need to be aware of hot water spraying out at you.


3. Lay down some towels
Avoid ruining your carpet and flooring and lay down some old towels underneath the radiator. Start with your radiators on the ground floor and work your way up as the air rises up the system.


4. Open the radiator bleed valve
To do this, you will need a radiator bleed key. The valve is round with a square inside and is usually located on the side of the heater towards he top. When the key enters, they should lock together, and you should be able to turn the key anticlockwise.

Do this slowly and carefully, you should hear a hissing sound as the air escapes. Try not to get too close in case the air is hot.


5. Be Wary
The key won’t need to be turned much at all, be wary of turning it too much as water will come rushing out. Hold the key until air stops coming out and water begins to drip, this means the bleeding is complete and you can turn the key clockwise to lock the valve. Repeat steps 3, 4 and 5 to all the radiators that need it.


6. Check the Pressure
Lastly, you need to check the pressure of your heating system, if correct, the needle on the boiler will be facing green and if incorrect it will be facing yellow.

If yellow, you should locate the central filling loop connected to your boiler. It looks like a tap and is connected to your main water, adjust this until the needle points to green.


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