I need to replace a valve on my upstairs bathroom radiator as the 'head' is cracked and the rad cannot be turned on brrrrr. There is a combi boiler system in the house. There is not a 'drain off' on the pipework for the heating. I assume that in order to drain down the system to replace the valve I need to: a. Turn off the water coming into the combi from the mains. The combi has a filling loop. b. 'Open' the pipework (by cutting) at a low point (ground floor) to allow the water to drain off - whilst about it may as well fit a new drain off? c. Bleed the radiators to allow complete drain off. d. Replace valve! e. When turning the water back on the heating pipework is filled again from the filling loop? f. Turn water and boiler back on. g. Re-bleed radiators (does it matter in what order these are done?). I think this will work, though confirmation would be great. My thought is that this is a lot of work to replace one valve. So firstly, is there an easier way of doing this? And, have I got it right if I go ahead with the method above?