Ive removed the radiator in my bathroom and will be replacing it with a towel warmer. My current pipes come out of the floor but the one with the thermostatic valve on it is too long. Ive been under my floor and had a look at the pipework. It is just a straight copper pipe going into a push fit connection under the floor. What would be the best way to do this without draining the system? Could I shut the valves to all the radiators and make up my new straight c/w new vave on top, and quickly swap pipes over or would there be too much pressure?