On Wed, 7 Oct 2020 23:35:03 +0100, John Rumm
wrote:

On 07/10/2020 22:37, PeterC wrote:
On Wed, 7 Oct 2020 16:11:49 +0100, newshound wrote:

Depending on the design, there is often a gate valve somewhere near tehe
tank (or possibly from cold cylinder to tank) that you can turn off
(recognisable by round pressed-steel handle).

Often won't move or, IME, turns 'off' but actually does FA.

or turns off and never turns back on again, with the spindle just
twiddling...
+lots
I've got 5 of those 22mm gate valves in my airing cupboard and none
now work properly, ranging from totally stuck, to failed fully open,
fully closed, or somewhere in between with wheelhead spinning freely.

Job added to to-do list - replace with decent lever operated ball
valves eg.
https://www.screwfix.com/p/full-bore...low-22mm/30584