i want to change the radiator in my bathroom for a towel rail radiator and need tochange existing valves to fit new radiator so do i need to drain system to do this.if so how do idrain the sysem.
you need to locate a drain tap on a radiator downstairs fix a hose pipe on the end and drain the system. no need to drain the whole system as long as the level is below your working level. (i take it is a house.) turn boiler off first. do the job then top back up by filling loop and bleed rads.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.