Should these valves stop my hot water?

[Harry Wood]

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

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 the 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.

Edited November 29, 2020 by Harry Wood

[ProDave]

I think the red handle in the top right picture might be the one, if the pipe from the bottom of it carries on down and then into the bottom of the cylinder.

 

the bottom left one I think goes to the heat input coil so is part of the central heating system not the hot water supply.

 

It is not unknown for gate valves to fail, particularly if they have been over tightened so it's entirely possible the valve is not shutting off.

 

If all else fails, go into the loft and tie up the ballcock then run the hot tap until you have drained the header tank dry.

[Harry Wood]

Thanks for that. I went with your suggestion to tie up the ballcock. That seems to have worked fine (hopefully the system refilled again correctly now too)

 

So yeah I think maybe that valve in the top-right may be broken then.

[ProDave]

3 minutes ago, Harry Wood said:

Thanks for that. I went with your suggestion to tie up the ballcock. That seems to have worked fine (hopefully the system refilled again correctly now too)

 

So yeah I think maybe that valve in the top-right may be broken then.

It is surprising how easy it is to strip the threads in a gate valve if you are heavy handed and that can leave them stuck open or shut depending where they were when you over do it.