Have taken off rads many times either to paint/wallpaper behind them or to replace with new one. Went through procedure of turning of all rads at both ends except the one I wanted to take off wall , turned off cold water supply and tied up ballcock in top up tank in loft ,turned off gate valve.
Drained water out of system which took a long time and was down to a trickle but not completely stopped. It was no problem taking rad off wall to blank cap off both pipes until I finished decorating ,a few weeks later.
However when I came to re-hang & connect the rad I started to take off the blank cap from pipe to connect the rad valve to pipe and water (cold) was coming out under pressure ?? Managed again to connect it but somewhere down the line and even though water had been drained a few weeks before there was a lot of pressure built up.
Not sure what direction to look in ?? The only thing that I can think of is the ballcock in top up tank although tied up was dripping over the time and therefore let water into system.Then again the gate valve which was new about 6 months ago and fitted to expansion pipe feed was also turned off.Need to take of hallway rad off next so need to look at this problem ,never encountered this problem before of real pressure in pipe.
Thank you
