I am putting in a new towel rail radiator where there was once a normal radiator, at the moment there are the two lengths of pipe that connected to the old radiator valves with stop ends on, there is also the drain valve (hose pipe) after this radiator, the c/h is operating at the moment, do I have to drain all the radiators before I can install the radiator now? also can I use the spped fit pipe and connections in place of copper