My wife has decided that as part of some up and coming decorating tasks, we need some taps changing in our en-suite bathroom. For the hot water we have the bog standard copper cylinder up stairs fed by a tank in the loft - the indirect cylinder according to this. It would seem therefore, that to change the cold water tap is pretty straight forward - just turn off the main feed into the house. For the hot water, I've got to turn off the feed from the tank in the loft to the copper cylinder (no problem, there is a stop tap in the way), then turn on the hot taps to drain the whole tank....which seems a bit of a waste. From the link, why don't they put an stop tap a position 7 so the hot taps can be isolated from the tank? If ever a hot water pipe bursts, the only way to stop the water would be to turn off the cold water supply to the cylinder and wait for the copper cylinder to empty into the house. The article also states that the heat exchanger in the cylinder is a run from the central heating and it's water heating capabilities are a secondary function of heating the radiators. If this is the case, why, when the heating is off, and the hot water on the timer is turned on, don't the radiators heat up?