Banging Pipework after Disconnecting Downstairs Shower? All aspects of plumbing questions and answers, help, tips and information

[justin79]

Hi,
I am hoping when reading this that a plumber or someone that has experience of banging pipes will help me rectify this problem.I have asked so many plumbers about this issue and I have tried nearly everything they have advised me on. This is the background to the banging pipe.
I had a shower disconnected from downstairs and the water feed was cut and capped. This did cause a slight bang upstairs and not long after the toilet (ball valve cistern type) made a huge shuddering sound causing the pipes to vibrate and random banging of pipes. I was due to have some work done on my house (new bathroom, kitchen, few near radiators and my stoptap moving from underneath floorboards to an accessible point) so was not to concerned with shuddering.
I have had the work done on my house but the banging still happens. I have tried the following: draining the system to cure air locks, turning down the stoptap, securing pipes to beams, changed the stoptap twice, checked the jumper in stoptap, main stoptap changed by water company, boiler serviced, checked water pressure (4bar), water hammer arrestor installed near the banging pipe, pressure reducing valve installed (not with water hammer arrestor) and asked my neighbour if they have the same issue, which they do not.
Having installed the pressure reducing valve the banging has decreased but the banging occurs near the stoptap. The banging happens at anytime even when I am not using the water. Also, I hear now and then a hear water gushing in the pipe followed by a bang but I am not running the water. All my taps are new and my toilet cistern is the new version (not ball type). Only a few times has the pipe near the main stoptap vibrated.
If your still awake, please please help as I cannot think what else to do. One final point, now and then when I flush my bathroom toilet it does bang but I do not know if this is coincidence as it bangs when I do not flush toilet.

Thanks.

[proptech]

HI justin79

If you are saying that this has only happened since the shower pipework was cut off, the most likely reason is that there is trapped air in the supplies. It may be the answer to cut back as far as their source.

[justin79]

Hi prop tech,

Thanks so much for the reply and advice. By 'cut back' what is it that you mean? I have been to the pipe where it was disconnected and capped and have released water or any air from that point. This is only a few inches long so not a long dead end pipe.

Also, the banging has transferred to near the stop cock and it only ever happens here and it does it randomly.

Thanks again,
Justin

[proptech]

I was answering you thinking "what has happened that's changed by only removing a shower"
There's many causes of 'water hammer' that can be easily found on the net, but I come back to 'what has changed'. Well, the water has been turned off, so a loose jumper in the stopcock could be somewhere to look at.

[justin79]

Hi,

Thanks again for your reply prop tech. I have looked on the net about water hammer and I have tried all methods that has been suggested so I'm really confused about the banging pipe.

The banging can be just one thump and then it can be a series of knocking sounds (one after the other). Also, I have changed the stop cock twice and checked the jumper so I am eliminating that.

One more point. Do you think it could be to do with my neighbour? I live in a semi detached we share the same mains stop cock outside. The reason why I say this is sometimes the banging does not occur til they come home. Then again it has happened when they are out.

Anyway, trying to narrow it down.

Thanks so much.
Justin