Hot water still flowing after isolation ?

[ronaldbiggs]

Hi

I need to replace a leaking compression valve on the hot water pipe in my bathroom upstairs, I have a combi boiler. I have turned the mains supply off via the stopcock and have opened all taps to drain the water.

Upon removing the compression valve the water continues to very slowly flow, do I need to turn the power off to the Combi boiler or isolate anything else to stop the water flow.

Thanks for any help you may be able to offer

 

[Burnerman]

Its a pressurised C/H system mate, with no connection between the C/H and hot water circuits.....assuming the leak is on the C/H side?
The leak will stop when the pressure in your system reaches zero on the gauge.....naturally you'll have to repressurise after to get the boiler working again.
John

 

[ronaldbiggs]

Thanks John,

The Valve that requires replacing is from the bathroom sink so I assume it would all be linked to the same system ?

 

[Burnerman]

Aha my apologies - for some reason I imagined the leak was on the C/H side.
No matter - turn the water off at the stop cock......if the problem is down stairs then opening a tap upstairs will cause residual water to drain down and then you can start work.
If the offending tap is upstairs, and there's no pipe work above that, then we can assume that the stop cock is still passing a little water, unfortunately (assuming there are no storage tanks in the loft of course).
John

 

[ronaldbiggs]

Thanks John

Yep it a leak upstairs in the bathroom, looks like its a call to the Housing Association to get the stopcock sorted, I was not certain if the combi boiler pressure was to blame with the continuos flow of water from the pipe after the compression had been removed.

 

[Burnerman]

Stop cocks can fail when the sealing washer gives up....a replacement of this means turning the water off in the street.
Its possible - if your nerve will stand it - to do repairs 'live' - which means that you relieve pressure by opening other taps in the house before getting stuck in!
As before, the pressure on the boiler gauge refers to the C/H side of the system.
John

 

[Gasop]

No need to turn off main stopcock with a combi boiler to work
on hot water.

Turn off the cold feed at the boiler.

Drain pipework from lowest tap/drain off.

 

[ronaldbiggs]

Thanks Guys, I will take a look at the boiler and see where the cold feed comes from, as for draining off I assume I can do this from the kitchen sink ?

 

[JohnD]

if you're working on a pipe to an upstairs tap, and there is just a small amount of water coming out after you have closed the stopcock, open the downstairs taps. This will also work if it is just residual water lurking in the pipes. Unless there is a lot of water, it will dribble out of the taps and there will be next to nothing at the place you are working.

You will have to use a compression joint. Unless the pipe is completely dry you cannot solder it.