your installer should of fitted a drain off point to your ch system where you would connect a hose to (generally lowest system point).
turn power off to boiler and connect hose to drain off and open valve. open upstairs rad bleed screws to let air in to help drain.
depending on your system set up depends on what drains. if the pipework for your chosen radiator comes down from above rather than up then you'll have to drain that radiator and pipework too before removal as it will be acting like a sump.
if you dont have a drain off, you'll have to drain from a radiator valve for example, turn rad valves both off, drain radiator and remove, connect hose to a rad valve and open valve to drain. you could connect valve to hose using couple inch piece of copper pushed into hose with nut and ring on to connect to valve.
complete your pipework, close bleed screws, make sure everthing nipped up and refill bit at a time from your filling loop (boiler off) observing for any leaks.
refill and bleed downstairs rads (fill, bleed and repeat as necessary), and then upstairs rads. check boiler pressure around 1 - 1.5bar. when all fully bled.
iain, May 2008
