banging from pipes

[joeinuk]

I keep hearing a banging noise from the walls near my bathroom(hard to say exactly), every 5 minutes or so. First, there is a small noise/knock/bang then 6 seconds later a louder bang. It seems to be getting louder.

I have drain the cold water system and then filled back up with the stop cock turned slightly so the water pressure isn't as strong as before. The banging is still happening.

This all seem to happen after next door had the water utility company out, who took up pavements outside after a water leak fused their electricity, a couple of months ago.

Could it be a faulty valve in the toilet cistern? air in the pipes that i have not got rid of? too much water pressure?

 

[tincup]

Hi

It might be coming from the ballvalve on the cws in the loft.

HTH

 

[joeinuk]

changed the ballvalve and still no joy with this. had a plumber out and he dosen't know what it is, just said it could be expensive to do a full investigation.
it is just constantly banging roughly every 5 minutes, each time followed by a bigger bang 2 seconds later. i can replicate it by turning the kitchen cold water tap off quickly, and the banging seems loudest in the wall in the bathroom.
the plumber turned the pressure down but this just made it quieter and obviously gives lower pressure in the shower etc.
he has since turned the pressure back up to normal.

 

[Armo74]

If you can replicate the noise by turning on the tap in the kitchen and then shutting it off I suggest you change the tap washer unless it is a 1/4 turn tap in which case its not uncommon for this to happen as the supply is shut off in a split second sending shock waves through the pipe work.

Alternatively you could install a shock arrester straight after the incoming mains stop tap.

Or you can try and locate the pipes and clip them correctly.

 

[doitall]

I would ask the utility outfit that did the job.