Bleeding a radiator made simple
If your central heating system is not running as efficiently as it might, your radiators may need bleeding. A simple way of testing this is by feeling the heat in your radiators. If the top feels cool to the touch but the lower part is hot, this is a clear sign that air is trapped in the system.
The air needs to be released from the central heating system so that it can work more efficiently. This is a simple task you can do yourself and is commonly known as ‘bleeding a radiator.’
First, check which type of central heating system you have. Is it a combination boiler or gravity-fed system? Combination boiler systems will need pressurising afterwards, so check with the manufacturer’s instructions how to do this prior to beginning.
You can find radiator bleed keys at DIY shops. Locate the bleed valve on the radiator; this is usually sited at the top left, right or back of the radiator. Insert the bleed key and turn it anticlockwise by half a turn. It is advisable to place a bowl or rag underneath the valve to capture any escaping drips of water. When you turn the bleed key, you will hear the hiss of air escaping. Once water starts to drip from the valve, turn it clockwise to close it.
Go around the whole central heating system checking the radiators in this way. If you have a combination boiler system, do not forget to pressurise it again afterwards, following the manufacturer’s instructions closely.
