MegaSack DRAW - This year's winner is user - rgwb
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Morning.
So -Â couple of days ago the household was woken by loud, intermittent knocking/rumbling/banging - it's like a low, thudding - if you didn't know it was internal it sounds a little like a helicopter passing over the house - it seems to be a vibration. Turns out it's the water pipes that are causing the noise. The problem is that it's seemingly at random, can last for hours or minutes and I can't for the life of me either cause it to start, or stop it once it's started.
If I listen to try to find the source I think it's on the cold-water, mains feed somewhere - doesn't appear to be hot-water related (I've bled all the radiators and there doesn't appear to be any correlation from a timing perspective to the hot water or heating being on or off). I've traced the pipes around the house and tried to work out where it's coming from and so far as best I can tell it's not coming from the (oil) boiler feed downstairs, but rather on the mains side of the house where it feeds the taps and into the water tank in the loft.
From reading around it seems like the most common causes are air-locks or hammering due to water pressure or something.I can turn the water pressure up or down on the mains feed and that appears to have zero effect.
I've tried bleeding all the radiators, turning off the cold water feed and bleeding the taps and cold water tank in the loft (turning every tap on, watching the lowest tap drain last, and then doing the same in reverse to try to get rid of any potential airlocks). Next on the list would be to try draining the hot water cylinder to see if that's full of sediment but I'm clutching at straws somewhat.
I can call a relatively friendly plumber but the problem is that there's zero guarantee that I can get his visit to correspond to the noise happening! We had it a lot on Friday, nothing on Saturday and intermittently yesterday.
Any suggestions appreciated!
It could be ball cock in your water tank in loft if you have one. Had similar problem as the ball cock had worn out and needed replacing. Causes random hammering in the pipes, very annoying but a cheap fix.
Margins right most likely ball valve in loo or cold water storage tank (if you have one).
ahhhh - cool. That might make sense - yes, we have a cold water storage tank in the loft. I checked to see whether we had any overflow etc but didn't take a look at the ball valve.
it's bloody annoying. I"ll see if when it's happening next I can isolate the problem by messing about with the valve / having it shut off etc.
..much appreciated BTW. Just wary of paying someone to come out without having a better idea of what the problem might be!
Cheers
Yes most likely a ball valve remember you’ve got them in toilets too probably.
I have also had problems with kitchen sink taps causing water hammer. Only happened twice but both times changing the tap worked.
Sometimes a tap washer can cause it too - it vibrates as the water flows but water has to be flowing.
It can be an expansion vessel not doing its job, but a float valve is more commonly the cause in a house.
Some valves can be braced against the side of the cistern, if flexing isn't the problem then a valve is on its way out
cheers again - will have a look - I suspect the ball valves maybe coming to the end of their working life - had to replace one in a cistern recently and it's a properly cheap bit of plastic. The one in the loft water storage tank is the same by the looks of things...