Can't find hot water shutoff valve in apartment

inigo

Hello. I want to change the taps in my apartment so I need to cut off water to taps. It's all electric, so no gas boiler or piped radiators. I have found the mains and cold water valves, but not the hot water's.

Photos below (sorry, don't know how to rotate them):

1. The brass and red valves next to each other below the shelf cut cold water off to the all the cold water taps in one go. That's bathroom and kitchen together. I have tested them one at a time and the result is exactly the same. Does this mean all the cold water in the apartment comes from the same place, i.e. I can drink water from the bathroom taps?
2. I think the the red valve above the shelf shuts off water into the cylinder but I haven't tested it. Do I need to empty the cylinder to shut water off to the hot taps or is it likely to be above the panelling next to the tank (if there is one)??

Thanks in advance for the replies.

inigo

Bump