Multiple Megaflows

[TangoTango27]

Hi All - before I start please forgive my total lack of plumbing knowledge!

We have a fairly large house and have 3 megaflows installed in our roof to provide sufficient water for the 4 bathrooms. However, our kids have now moved out leaving just me and my wife in the house.

Now, presumably when the boiler comes on to heat up the hot water, it will be heating up the water in all 3 megaflows at the same time which will take 3 times as long as it would if there were only one megaflow? But as there are only 2 of us in the house now we don't need as much hot water so I want to know if I can shutoff 1 or even 2 of the megaflows (without damaging them) thus heating up a smaller volume of water which I would hope would happen more quickly and using less gas. (I would then turn on all 3 megaflows if we have guests to stay and need more hot water.)

Am I correct in my thinking and if so, which of the 3 megaflows should I shut off and which of the numerous valves on each megaflow would I need to turn off to achieve this?

Many thanks in advance for any advice you can give me.

 

[cross thread]

It would need looking at as it could be piped in various ways ,the cylinders notin use don’t want leaving with stagnant water in.

 

[muggles]

There's the potential for legionella and other bacteria to build up in the cylinders that are isolated. They'd need thoroughly flushing and treating prior to bringing them back online