Concerned I have a problem with my hot water system

[voicey]

I fitted a new sink and tap into my garage yesterday which meant I had to shut off the water to fit new isolation valves. The cold was no problem as the stopcock was right next to the sink. However the hot side did give me issues.

I bunged the supply from the main tank as well as the vent - in the past this has proved enough to cut off the hot water and indeed in the 1st floor bathroom the hot tap did stop running. However, downstairs the hot tap in the kitchen ran (albeit slower than normal). This also mean that where I had to remove the old tap hot water was still flowing. I managed to get the valve on by working quickly but would like to know what could cause this.

I should point out that I used the bunging method successfully 4 weeks ago to put isolation valves on the ground floor cloakroom so don't think it is a system layout problem.

Any advice would be gratefully received - cheers!

 

[Burnerman]

It would seem that your bungs weren't fully sealing, and allowing some water or air to pass. If a hot tap was slightly open, this would give the same issue.
So long as you have hot water to all taps, it indicates that there isn't an air lock, either.
John

 

[voicey]

It would seem that your bungs weren't fully sealing, and allowing some water or air to pass. If a hot tap was slightly open, this would give the same issue.
So long as you have hot water to all taps, it indicates that there isn't an air lock, either.
John

Thanks for the reply. I have hot water to all taps now.

I would have thought that the bungs would have either worked or not - I managed to stop the hot water at the 1st floor taps just not the ground floor. Would the small difference in head matter?

 

[Burnerman]

Its one of those 'maybe' answers I'm afraid - if the pipe that you had open managed to glug a gulp of air, then all water retention would have been lost and the pipe would run for evermore.
The bungs that I use have become so hard now, its time to replace them - but a potato bunged over the expansion pipe works well!
You've got your job done anyway, so thats a good outcome.
John

 

[voicey]

I revisited this today as I am fitting a kitchen next week and thought it'd be useful to be able to stop the hot water.

I fitted new full bore isolation values to both the 22mm pipes exiting the tank. I also fitted a push fit end cap over the vent. With the valves closed and the cap in place I can stop all low pressure cold water and the hot water upstairs.

However, downstairs I still get hot water, accompanied by some banging in the system somewhere. I suspect the hot water system is breached somewhere - would the likely culprit be the hot water tank coil?

Cheers!

 

[mcmoby69]

check the cylinder hasnt collapsed. sometimes its best to leave the vent uncapped.