How to drain only hot and cold feed to a bathroom which is on a drop from an Unvented cylinder.

[xpritt]

The system has an unvented hot water cylinder which heats the water upstairs (via an immersion heater) and I need to drain down the pipes so I can move the two pipes feeding the sink in the bathroom. There are two showers (on a separate drop) one bathroom (on it's own drop) and one sink elsewhere (on it's own drop).

Am I right in thinking I can turn off the cold water supply into the property, turn off the cylinder and just open the taps? I've done some research and it sounds straight forward but I have read about cylinders imploding so I'm a bit worried about blowing it up as I'm doing it for someone as a favour.

 

[sammathias]

Yes isolate cold main then open hot and cold taps on the floor below you wish to work then open taps above.

 

[xpritt]

Yes isolate cold main then open hot and cold taps on the floor below you wish to work then open taps above.

Thank you I was just worried about the implosions I'd read about but it sounds like this is only the case if something is seriously wrong with the installation.

 

[dan_the_plumber]

No you only need to worry about negative pressure (sucking back) if there is no tap above the cylinder.
It’s like holding your finger over the end of a straw then drawing it up out of your Coca Cola. Take your thumb off (open the taps) and the vacuum is released.