Open the drain valve anti-clockwise, using the adjustable wrench.
The air vents are now ready to be opened. It is important to begin upstairs initially, opening the vents anti-clockwise with your radiator key. A sucking noise should emerge – this is the sound of air entering the radiator.
Once all the upstairs air vents have been opened, inspect the hosepipe outside to ensure that water is coming out of it. Leave for 10 minutes, or a touch longer with cast iron radiators, before repeating the process with your downstairs radiators.
If, after 10 minutes has passed, water is still emanating from the downstairs air vents, this might be due to the radiators being individually piped from upstairs. Should this be the case, the radiators will have to be drained down individually using the radiator drain valves. After the hosepipe has stopped draining, you’ll be ready to commence with any work necessary.