I'm trying to shut off the hot water supply to repair the kitchen tap. Unfortunately I can't see any isolator valves near the tap, so I'm puzzling over how to shut off hot water for the whole house.

I tried to do a bit of research into how our heating & hot water system works, but I may be getting this wrong, and to be honest I'm kind of tempted to just post the question "What the heck do all these pipes do?", but I shall try to be more specific.

It's a F&E system with two tanks in the loft and hot water cylinder in the first floor airing cupboard, which looks like this:

airing cupboard pipes

So according to these instructions I need to close a valve which feeds cold water into the bottom of the cylinder. "This valve should be easily recognisible as a valve with a red, wheel-shaped handle on a pipe that runs from the ceiling of the airing cupboard to the bottom of the cylinder."

The valve in the top-right (just above the top shelf) seemed to fit that description, so I tried closing that.

Then I noticed valve in the bottom left could also fit that description, so I've tried closing that too (although I may be misunderstanding the direction of flow there)

I notice there's three pipes leading into the bottom of the cylinder. The third one slightly higher on the left is hopefully shut off by the motorised valve (I have the heating and hot water switched off)

I then try running the hot tap for a minute or two, but it's showing no signs of stopping. Do I just need to wait longer for pipes to drain out? I tried the same on the 2nd floor bathroom because I thought it might stop flowing quicker there, but ...no sign of stopping.

  • 1
    upvote for your ransom-note looking pastiche of photos there. Well done!
    – Willk
    Nov 28 '20 at 17:49
  • Channling David Hockney there, the red handle at the top right looks most promising. but I'm not convinced that is is cistern fed due ti there bing no vent pipe.
    – Jasen
    Nov 29 '20 at 4:43

When in doubt, find the main shutoff valve to your house and turn it off. That will shut off the pressure to hot an cold systems so you can do your repair work..

  • I got another suggestion today, which was to tie up the ballcock to prevent the feeder tank refilling, and then let that drain out. So I did that (first leaving a hot tap on to double-check which tank was feeding the cylinder). The repair is done! Maybe that was a good "when in doubt" way to turn off only the hot water, but I just realised you're absolutely right, particularly as I also needed to turn off the cold water for the repair anyway, I guess I only needed to use the main shutoff (and then drain that same tank). Didn't need to tie the ballcock.
    – Harry Wood
    Nov 29 '20 at 22:39

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