banging pipes, water hammer

[doingmyheadin]

Hi all I wonder if anybody can help me, ok basically we live in a council owned four bedroom house, with a condensing boiler with a sealed central heating system, recently we had a new sink and taps fitted in our kitchen downstairs and then a short while afterwards our problems began..when ever would turn the COLD water off at the kitchen sink the pipes would bang but also when the water isnt running we get random banging at all times again coming from the cold pipes which is so annoying! We rang up council who sent the original plumber who fitted the taps and sink he came and said it must be faulty tap unit?and so he came back today and fitted another set of taps but it still banged when u turned off taps and still randomly banged when water isnt running, so he said it must be a pipe touching or something? He checked the pipes in kitchen stillcouldnt see problem, so got another plumber to help, they then fitted a third set of taps and still the problem is there so then they thought it could be a faulty shutoff valves that he fitted to be able to turn the water off to fit new taps as stopcock is really stiff, they were here 3 hours and finally said they fixed it and I asked what problem was and they said was a faulty valve under the sink great I thought no more banging and i turned off tap and it didnt bang, so I tried the electric shower to make sure it still worked as it runs from the mains and then the banging came back again! So now the plumber is saying it must be a faulty stopcock thats in the kitchen thats really stiff? Im not a plumber but could that be whats causing it? Opening the bathroom tap upstairs doesnt make the banging noise but turning off the electric shower does? Could it be the shower? Plumber says its not that or the washing machine? Also says cannot turn the water off outside property cos cannot get to outside stopcock so they have to come and dig up garden to put a new stopcock outside so he can turn off water to propert so he can put a new stopcock inside lol, im not convinced he doesnt seem that sure but I cant beleive he hasnt come across this problem before? Can anybody help? Can it be the stopcock causing all the problems, just to note before the new sink was installed we didnt have problem and he said he didnt change any pipework? Oh the house was built in 1950s and I assume its the original stopcock, any help would be appreciated.

 

[bigmondy]

Notoriously difficult to diagnose as hammer can be caused by numerous contributing factors. A prv may be a solution on the supply to the shower. Not sure replacing the main valve will help but they have to follow a process of elimination. The random banging may be caused by neighbours on the same supply line having appliances connected that open and close their supplies quickly?!

 

[kris]

Hi there doing my head in and welcome to the forum,,,,,These plumbers should really be doing the elimination process, IMH when you hear pipes banging folks always say your pipe mustnt be lagged inside the wall but theyre not finding the cause of the banging, in my experience it tends to be valves with certain inards where there is pressure , so youl usually find it on cold water mains, your plumbers fitted 3 sets of taps, i wouldve been looking at either the main stopcock or any other CW isos that are under the sink after the first new set went in, i put isolation valves on everything that i do , so i wouldve shut off the supply to the new tap then tried to see if fault still there , the chances are with the first tap going in the old stopcock was turned and probably hadnt been turned for ages so id be looking at that but id be eliminating other things where poss aswell,

 

[doingmyheadin]

Thank u for replies, yes the stopcock is very stiff and the plumber had to use I think its called a stinson? To turn the tap as its almost seized, its the random banging when no water is being used that concerns me most as I could live with the hammer when turning the tap off but the random banging at all hours is getting to me u can hear it upstairs over the tv! So what u guys are saying it could be that old stopcock thats causing it? I can understand it doing it when tap is turned off but not when its late at night and there is no water running? Im anxious that the stopcock replacement wont fix it and if it doesnt what would be next step? Replace shower? Pipes etc? Oh one thing i forgot to mention is my next door neighbour has recently had a new extension to back of their house snd their property joins on to mine could that be to do with it? I asked plumbercand he said no?

 

[Jay Jay]

Thank u for replies, yes the stopcock is very stiff and the plumber had to use I think its called a stinson? To turn the tap as its almost seized, its the random banging when no water is being used that concerns me most as I could live with the hammer when turning the tap off but the random banging at all hours is getting to me u can hear it upstairs over the tv! So what u guys are saying it could be that old stopcock thats causing it? I can understand it doing it when tap is turned off but not when its late at night and there is no water running? Im anxious that the stopcock replacement wont fix it and if it doesnt what would be next step? Replace shower? Pipes etc? Oh one thing i forgot to mention is my next door neighbour has recently had a new extension to back of their house snd their property joins on to mine could that be to do with it? I asked plumbercand he said no?

Hi put a shock arrestor (mini expansion vessel)by sink/ boiler on cold and pressure reducing valve on incoming mains job done!