Advice over noisy pipe leading to cold water tank

[Chrispee]

Hi,

I've had a long running problem that I'm looking to get some advice on. I live in a 2nd (top) floor flat with loft access and a cold water tank in it. This feeds my vented CH system (heat only boiler and HW tank). Every once in a while, perhaps between 4-8 times a day, i get a loud vibrating through the pipes that sounds like an electric sander ( trapped air?) I believe this is the pipe that leads to the cold water tank. It doesn't seem related to when I flush the loo, use cold water from the taps or when the heating/hot waters on.

I dont know if the tank feeds the flats below me as well so maybe it will be an uphill battle if it could stem from something involving neighbours. Advice or experience on whether it supplies the whole block would be appreciated. When leaving the building today we could hear the noise as clearly in the foyer as in my flat. So far I've had a plumber change the tank float valve (or just the diaphragm, i'll need to check) but no improvement.

Separately (not sure if related) my loo is slowly draining its cistern of its own accord by what looks like a dodgy flush valve, could the two be related or totally coincidental?

Any advice would be appreciated, given its a difficult time to get a professional in!

Any help would be appreciated. Thanks!

 

[steadyon]

Why not try turning off the feed to the inlet valve of your WC for a day or so (assuming it has an isolation / service valve), and see if that makes a difference. You could flush with buckets of water in the interim.
It's possible a slow leak causes you inlet valve to open ever so slightly to maintain level, so instead of cutting off relatively sharply, its vibrating. Could also cause the same in the cold water storage tank.

 

[king of pipes]

Sounds like you need a plumber we are carrying out emergency work so i suggest you employ one to fix the problem. Kop

 

[Chrispee]

Thanks both. I have a stopcock in the bathroom that shuts off all water but the loo is boxed in so cant see a separate valve. Will try this later today and get the plumber back for the leaking cistern.

Was after some general thoughts about the probable layout for cold water in the building, if the cold water tank only feeds my flat or the ones below me as well.

The fact the problem is so sporadic means its difficult to really pinpoint without having someone here for hours potentially waiting to hear it!

 

[Chuck]

Why not try turning off the feed to the inlet valve of your WC for a day or so (assuming it has an isolation / service valve), and see if that makes a difference.

If there is no 'servicing' valve for the WC, take the lid of the cistern, rest a piece of wood across and tie up the float valve with a piece of string.

I think it is likely that there are two problems (leaking flap valve in WC) and water hammer probably due to a worn fill valve on the tank in the roof. The former is provoking the other.

If you're DIYing, fix the loo first as that might do the trick, at least until the valve in the roof gets worse. If you are going to use a plumber, get them to look at both so you only have one call-out / minimum charge to swallow.

 

[Chrispee]

Sorry for the slow reply, and thank you all for the advice. We have used a knife to keep the WC cistern float up so it doesnt fill then leak when not in use, but the pipe noise still happens sporadically despite this. Could it be air getting trapped somewhere or a blocked vent? A plumber did look at the fill and float valves but at the moment says he cant source a replacement as the suppliers are not stocking the correct model. I need to speak to the freeholder about the water tank as it may be their responsibility. I don't own the loft space. Will keep this thread updated