water Hammer

[Brent pullen]

I have a customer that has a water hammer problem which he has asked me to fix.
The problem started after he had a worcester combi installed (not by me). The problem is on both hot and cold and the pipes bang/knock when the outlets are opened . He has 4.5 bar of water presure with flow of approx 19 litres a min .
I have fitted a small shock arrester which has reduced the problem but has not overcome it . I have even tried a presure reducing valve this has not worked either.
I am at a loss as to what to try next and could do with some help/suggestions .The pipework is not accessable as is boxed in or under floor boards.
would a larger expansion vessel sort out the problem?
Any suggestions would be greatly appreciated.

 

[oldplumber]

Probably due to insufficent pipe clips and having the system under pressure now if it was gravity fedbefore has allowed it to be come apparent. Try and trace the noise source and lift a few boards.

 

[tamz]

would a larger expansion vessel sort out the problem?

Possibly, as would the seeming long forgotten and seldom used things called pipe clips

 

[tamz]

Oldplumber beat me to it