depending on the types of rad valves you have no need to drain boiler. if the valves are thermostatic then turn them to the lowest possible setting (normally 0 and only on one end) you will also need to close the other valve at other end fully clockwise to ensure off. Be aware that when undoing the 2 nuts between valve and rad there will be some pressure and possibly dirty water so best put some sheets down! as water flow slows open bleed point to aid. when ready to put rad back connect as usual open both valves and open bleed until water comes out. If your boiler is a sealed system (pressure gauge on boiler) then you will need to repressurise until reaching 1 - 1.5 bar, if conventional system, tank in loft, then system will self fill.
andy, July 2007
