Hot Water Shut Off

[AverageDIY]

This weekend I am going to be replacing the hot and cold isolator valve under the kitchen sink for the sink tap.

I realised that I have no idea how to turn of the hot water supply in this house (recently moved in).
I have installed isolating valves (compression type) before on the hot water supply for taps in my old (small) house but that just had a combiboiler and was straightforward to turn of the hot water supply.

The new house has a cylinder in the airing cupboard, with another two much smaller cylinders above. I think this is called an 'unvented pressurised system'. There is no water tank in the loft.

The question I have is how do I turn off the water and possibly more importantly how do i turn it back on!
Both being off at the same time is fine I guess, though I would rather do one then the other.

The cold is directly connected to the main so thats straightforward but what about the hot water?
There is a stop-tap looking valve to the right of the cylinder which i am guess (but not sure) is either cold water in or hot water out.
That would likely be my first guess!

Thanks.

 

[twgas]

If you have an unvented cylinder, turning the cold, incoming main off will also turn the hot off.
If you jhave spare new inserts why not use them although I doubt it would matter if the old ones were left in place.