There may come a time when your radiators have become air-locked. If so, the guide below explains how you can remove the air and increase the efficiency of your radiators by bleeding. NOTE:Every domestic radiator has a bleed valve fitted. They are normally sited on the top corner of the radiator, either left or right side. This is a recess with a square metal block sat in the centre. This is made so that a bleed key can fit over it and then can be opened or closed. This key is small and has the correct sized and shaped recess to accommodate the square block. Eltham Plumbers carry all types of bleed keys.If you do not hold a bleed key, they can be bought from most plumbing retailers.Method: 1). Isolate the boiler and check the circulating pump is also turned off. These pumps often have direct live feeds.2). Place the bleed key on the block and turn very slowly anticlockwise for only a quarter of one turn. This should be enough to begin allowing the air to vent. You should hear the air begin to hiss as it leaves the radiator.3). Ensure the radiator bleed key stays on the block so as the air stops there should a slight dribble at which point you turn the valve (or block) off. An Eltham Plumber will carry out this job if you are not confident and will also guarantee the work. Check: If no water appears as you bleed the radiator, make sure that the feed and expansion tank in the loft is not still full. If so, the valve probably has a blockage. 1). Close the radiators inlet and outlet valves fitted on both bottom corners, and take out the screw from the centre of the bleed valve. 2). Using some small gauge wire, clear the blockage, and then open up one of the radiator valves slightly to produce some water from the valve.3). Close the radiator valve and refit the bleed valve screw. Open both radiator valves and re-test Also check for any leaks.