Hot water gate valve

[Hobsini]

If I turn off the gate vale on the pipe running directly into the bottom of hot water cylinder, should the hot water supply to the taps stop almost immediately? I've done this but the hot water still runs. I thought cutting off the cold water feed would stop hot water being pushed out of the top of the cylinder and would therefore stop the hot water immediately. Is this wrong and do I need to run until the cylinder is emptied? I am trying to change a tap without draining the system.

 

[lightning]

May take a few seconds , if hot water doesn’t stop then gate valve passing not shutting off completely

Paul

 

[Hobsini]

Ran for a few minutes and didn’t stop. If I run until the cylinder is empty then will that help or am I back to draining the system? Any other options?

 

[FiremanT]

Ran for a few minutes and didn’t stop. If I run until the cylinder is empty then will that help or am I back to draining the system? Any other options?

If the valve is notclosing properly, the CWS will keep filling - it will never stop!

CAUTION: Most gate valves are poorly constructed. If you try ti hard there is a massive danger that the spindle will snap, leaving the gate in the closed position. This makes draining or changing the valve a lot harder and potentially messier. Isolate CWS at either it's inlet valve (if one exists) or the mains stopcock. Drain the CWS, and replace the gate valve. If you do not feel confident, engage a plumber. Ideally, replace with a full bore lever valve or a QUALITY gate valve, such as PEGLER. Don't buy a £2 one

 

[oldbuffer]

1. Are you sure it is a gate valve into the cold feed to the bottom of the cylinder you are turning? Quite often there is a gate valve on the coil to enable the flow to the cylinder to be balanced with the rest of the heating circuit.
2. A picture of the cylinder and valve would be helpful.

 

[terryplumb]

Bung the loft tanks outlet that feeds the cylinder. Run hot taps ,for a minute and they will stop.

 

[Hobsini]

Hi, thanks - I assuming if I shut off the cold and drain the cold water then this would have the same effect i.e. no need to drain the hot water?

Pics of gate valves - first one is the one I shut off. Second is on a pipe that runs to first but also splits off before that.

 

[ianmcd]

Impossible to tell from your pics as they dont show anything really, try closing the valve on the right hand pic,the lower down one could be a restriction valve for the HW heating circuit

 

[Hobsini]

The first pics gate valve goes directly into (and is immediately before) the cylinder so I assumed that was the right one. Am I ok turning off any of these valves and testing the effect? Is there any potential to cause a problem by doing this? There are also a couple of lever type valves in the airing cupboard - same applies to these?

 

[terryplumb]

Not wise haphazardly operating gate valves ,they are notorious for not closing fully ,snapping internally (in closed position).
And some are set in partially closed positions deliberately on c/heating pipework.
If you bung the outlets in the loft tank you will stop the hot water flow at taps.
If you don't want to do that you can close the feed to the loft tank or tie up it's ball valve ,then run hot water taps ,or any cold taps that are fed from the loft tank. Once the loft tank is emptied no water will flow from hot taps.
Unfortunately this wastes water including stored hot water ,and the cylinder will be full of cold water.

 

[denso13]

Pics of gate valves - first one is the one I shut off.

Hard to tell but one looks like the return from the coil and the other looks like 15mm. Could be that neither are on the cold fed from the storage cistern.

 

[Elkato531]

My money would be on the lever valve being the cylinder cold feed. Feel down that pipe and see if it goes into the bottom of the cylinder. It may be round the the back as its usually on the opposite side to the coil tappings.