hi, im looking to change my upstairs radiators for new ones, inc lockshields and trv's. my system is a heatline c24 combi boiler so no f&E etc in loft. whats the procedure for removing rads?? do i have to drain down system?? or just turn off main stopcock, turn off boiler etc. i understand the procedure for removal for decorating purposes and understand the fitting of the rads etc, its just the system the heating is on that im not 100% with, dont wanna go for a swim when i remove the lockshields etc thanks 
