Radiator (bleed)

Fitted on each radiator in the chain there is a bleed valve on one of its top corners, this is a square shaped block in the middle of the fitting. A key is needed to undo this valve. Installers such as N9 Plumbers carry all types of these keys. However if no key is there, they can be bought from most plumbing outlets. Having turned off the boiler and isolating its main pump, with this key, turn the block anticlockwise for a quarter of a turn. It isn’t necessary to turn it any further than that, but just in case of opening too much have a container ready for any spillage.

The process can’t be done quickly, in other words by opening the valve further than is needed to let the air out, because it is likely to encourage a mass of water to empty all over the floor.

When the air begins to escape you will hear a hissing sound. Make sure that the radiator bleed key stays in place on the block so when the air stops and a dribble of water appears you will be able to immediately close off the radiator to prevent a flood. An N9 Plumber can carry out this task if you are not confident or unsure and will also guarantee the work is done correctly. If nothing is present when you bleed the radiator, see if the feed and expansion tank in the loft is empty. If full, then the valve is blocked. Close the radiator down with the inlet and outlet valves at each end, then remove the screw from the middle of the bleed valve. With a piece of wire, clear the blockage and open up one of the radiator valves slightly to produce some water from the hole. Shut the radiator valve and refit the the bleed valve screw. Open up both radiator valves again and again test the valve.


“