Smart meters, less smart companies

[Owen Smith]

Edit: It is not a pressurised system.

Then the main stop cock would not have helped for some time, the entire hot water header tank in the loft would have to drain down through the hot cylinder before the leak stopped. What would have helped is the airing cupboard usually has a valve to stop the header tank supplying the hot cylinder. And you really ought to get your stop cock fixed. Or at least find where the one in the road is for your house, though that may also have seized.

 

[Owen Smith]

What's the service life of the O rings?!

Longer than the seals in the isolator valves. I generally find by the time anything fails the isolator valves are useless and either won't turn or spray water out of the gland.