Water Hammer

GreeBo

I have what appears to be water hammer from my (downstairs) kitchen sink, on the hot water tap. Its a lever mixer but if you shut it off quickly when its on hot there is a shocking clanking noise.
Shut it slowly and there is no problem.
Where do I need to start looking?
Ive read a bit but some of the solutions sounds very complicate, read expensive.
Is there a cheaper place to start? I read somewhere that it might just be the seal on the tap??
Ive had a few floor boards up to try and trace the knocking but it runs under tiles in the ensuite upstairs and I dont want to have them up.

Cheers for any advice.

Gordon Gekko

I had this problem recently, and after much internet research, traced it to a new 90 degree bend we put in some piping - apparently the water rushing through constricted areas like a sharp bend causes noise and/or vibration in the pipes - it used to be a really freaky high pitched whining whenever we flushed only the upstairs toilet or used only the cold taps.

The weird thing is the noise has stopped completely in the last week or so.

Anyway, point of this post is to check if you have any tight bends in your piping that may be causing it.

That could only be one cause of it however!

GreeBo

Hmm all the bends are right angles as its all copper piping...
After some rummaging around in the floor boards above the boiler/stack I have kinda traced the problem to the hot pipe coming from the cylinder
I have also started to notice that if I walk heavily across this area that I can hear the pipe vibrating, same sort of noise but not as bad
Looks like its time to take the floor boards up

If I just add some brackets could I be hiding the noise but making the underlying problem worse?

tapest

Yep, been there
As gordon says...If you had any new piping installed /changed recently, that's the 1st place to look. I replaced a toilet cistern and was too neat with the pipework, a double "S" bend in very short length. Hammering was heard all the way back to header tank. If no work done recently let us know...I'd like to keep an eye on other possible answers
t

tapest

GreeBo wrote:

Hmm all the bends are right angles as its all copper piping...
After some rummaging around in the floor boards above the boiler/stack I have kinda traced the problem to the hot pipe coming from the cylinder
I have also started to notice that if I walk heavily across this area that I can hear the pipe vibrating, same sort of noise but not as bad
Looks like its time to take the floor boards up

If I just add some brackets could I be hiding the noise but making the underlying problem worse?

Don't pull floor up yet...Give other posters a chance to respond. Changing pipe layout in other place on the run might solve problem. Test by removing short pipe section (or just a bend) and replace temporarily with flexible pipe (metal covered...used now under sinks....someone tell him what it's called). Like the good tailor ..measure twice & cut once
t

GreeBo

Well I've changed nothing but the noise has been there since we moved in a few months ago.
I havent noticed any new looking pipework and Im assuming that this noise is new enough as its not something the original owners would/could live with.
The house was rented for 12 months before we bought it.
I think I will take a look at the actual tap first, though I *think* I have heard the same problem to a lesser degree from the ensuite shower, which is also a lever tap, again on the hot feed.