I hope this isn't a too silly question, I have to shortley turn of my cold and hot waterto do some work. I have a combi boiler so know u just turn off the outlet hot water valve on the boiler. For the cold , due to an old lead inlet cold water pipe, witha dodgy stop cock, i will have to turn the cold off at the meter in the driveway, has a new stopcock there. My question is , is there a proper order in turning the hot and cold water supplies back on. I assume i should do the cold first , then turn on the combi hot water valve. Is that correct, and am I likely to get air locks etc in the hot water system, or will the mains pressure push these out