Central Heating ?

In your loft you should have a water tank, near to that , there should be a smaller "header tank" which automaticaly tops up the central heating water...Lift the lid / cover and you will discover a float on a ballcock..Lift this up and tie in position (This will stop any water from filling this tank, when the rad's are bled)
Go now to a radiator in an easy to clean area, i.e. a Bathroom, and with your radiator key, let about a bowlful of water out of the rad. (This could be messy, as the rad water gets filthy )
Once this is done, go back to the header tank, tip your de sludger in, release the ballcock, and Robert's your Mothers brother!!!

CHUM
October 2009