1. While your heating is on, carefully feel the tops of each of your radiators to check if they are warm. Those which are cold at the top need bleeding.
2. Switch off your central heating, and let the radiators cool down before bleeding radiators.
3. Look at the valve on the top of the radiator some need a screwdriver to undo them, but for most you will need a radiator key.
4. Holding a cloth underneath the valve to catch any drips, slowly turn the key anticlockwise to open the radiator valve. You should hear hissing as the air escapes.
5. When the hissing stops and water s