Can I leave valve open to unvented indirect cylinder?

[eamon1]

Hi! I've recently moved to the UK from a warm country and am trying to figure out how heating works.

My flat has a megaflow unvented indirect cylinder (pictured) with a honeywell motorised valve connecting it to a communal boiler system. I am living in a council flat in London. When I first moved in there was no hot water, so a plumber from the council opened the valve and soon I had hot water. However, he mentioned that I'd only need to leave it on for 1 hour a day to get enough hot water from the communal system. He mentioned that the thermostat was not connected to the motorised valve, so I'd need to control it manually or install a control panel.

I have a few questions:
1. Is it safe to leave the valve open all the time? Hot water flows into the flat in 6-hour on/off blocks, so I'd assume that the cylinder wouldn't constantly be receiving heat. However, I have heard that cylinders can explode, and I've heard conflicting advice from different tradesmen (one said it's fine to leave open, another said it's not). Also, this flat had a previous tenant who was obviously fine with the setup. Perhaps she just left it open all the time.
2. If it is not safe, how much would it cost to automate the valve?
3. [perhaps not the right forum] How do council flats get hot water in the summer? I've been told that heating is only on for ~30 weeks a year. Perhaps heating for the radiators is on for ~30 weeks, while heating for the cylinders is on all-year?

Thank you!
Eamon

 

[flameport]

1 - no, it's been installed incorrectly.
2 - nothing,. Council flat = council pays for any repairs.
3 - radiators may well be on for 30 weeks but hot water should be available all the time.

 

[eamon1]

Thank you! I will look into getting it set up correctly.

1 - I am curious what the previous tenant did for her hot water, then.
2 - I am now the leaseholder of this flat so I think I'll be on the hook to pay for any alterations