hi i rescently moved my brothers tiolet and stopcock in his house which is a combi system, i knocked the main supply off and then drained the coldwater by opening the taps. after changing the stopcock and moving the toilet evreything was fine ,but a few days later my brother said the central heating was making a a banging noise since the jobs were done? would this affect the central heating or is it coincidence? if it was my fault how could i have got round this? cheers scott.