http://www.google.co.uk/search?q=water+hammer
Seems it can be casued by lots of things. And there are different causes depending on the exact types of noises.
David
Hi,
Recently changed a washer in my bath cold tap.
Now, when you turn it on and off, there is a right "thud" through the water system.
Makes funny resonant noises sometimes as well.
Any ideas anyone?
Pat...
Sounds like trapped air in the system, not being a plumbing expert I wouldnt know how to, but i guess you will have to bleed it somehow.
I dont, but google has loads of answers:
http://www.google.co.uk/search?q=water+hammer
Seems it can be casued by lots of things. And there are different causes depending on the exact types of noises.
David
Is the tap, tank or mains fed?
If it is tank fed, you may have an airlock.
Take a hose from your mains water tap (probably outside) and run it and fix it to the bath tap. Next turn on the bath tap first.
Then turn on the mains tap for 20-30 seconds. The higher pressure will force the air up and back to the tank. Job Done! 
[Edited on 15/2/06 by nitram38]
[Edited on 15/2/06 by nitram38]
quote:
Originally posted by nitram38
Is the tap, tank or mains fed?
If it is tank fed, you may have an airlock.
Take a hose from your mains water tap (probably outside)
Pat,
Did you turn off the mains stop cock to do the job, if so it's possible the "jumper" in that is resonating.
HTH
ATB
Simon
if you have a mixer tap in the kitchen, just turn both sides on and block it with a finger. Hot side doesnt have a valve to my knowledge.
Clunks in my experience are usually down to loose pipework, though that seems unlike here if you havent changed anything!
could be that before you turned off the main stop tap it was only open a couple of turns, if youv'e now fully opened it, the water pressure will
be higher, try closing it down and see if that helps.
As said earlier it should be fed from the main
so it shouldn't be air locked, i use the word should, because it's amazing what you find in some houses.
[Edited on 15/2/06 by Wadders]
quote:
Originally posted by JoelP
if you have a mixer tap in the kitchen, just turn both sides on and block it with a finger. Hot side doesnt have a valve to my knowledge.
Clunks in my experience are usually down to loose pipework, though that seems unlike here if you havent changed anything!
quote:
Originally posted by Wadders
could be that before you turned off the main stop tap it was only open a couple of turns, if youv'e now fully opened it, the water pressure will be higher, try closing it down and see if that helps.
As said earlier it should be fed from the main
so it shouldn't be air locked, i use the word should, because it's amazing what you find in some houses.
[Edited on 15/2/06 by Wadders]
quote:
Originally posted by MkIndy7
quote:
Originally posted by nitram38
Is the tap, tank or mains fed?
If it is tank fed, you may have an airlock.
Take a hose from your mains water tap (probably outside)
The Kitchen sink should ALWAYS be Mains water, at least thats inside!
And maybe the tap washer could be upside down if possible?, or wherever you shut it off to change the washer needs opening fully or throtteling down a bit.
Your quite right, i missed the bath bit, thought we were talking about kitchen taps. Still be amazed if its air though.
If the cold tap in the bathroom is tank fed, then it would have nothing to do with the stopcock. Some houses are still tank fed.
[Edited on 15/2/06 by nitram38]
I did use the stopcock and I think it is manis fed as it will stop running after a minute or so after the stop cock is turned off.
Surely must be something to do with the washer.
The tap does seem to be on or off now as a pose to progressive water.
Do the washers have an up and down as it looked symetrical to me.
First one I'd ever done though and was a cheap B&Q washer.
I can swap it with one from the sink and see what happens.
Pat...
Pat,
Reason I mentioned it was a friend had similar noises and that's what plumber (and friend) suggested.
This may help (number 8)
http://www.iphe.org.uk/consumer/techfaq.html#15
ATB
Simon
The quality of the washer shouldn't be a problem as long as it seals when the tap is turned off. Open the cold taps when the stop cock is turned off, then turn it back on and open it till the water hits the bottom of the sink without bouncing back out so there isn't too much pressure, then turn the taps off. It sounds like you've opened the stop cock too far.
id guess the washer was different, its making the water start and stop too fast, which is making loose pipework bang that wasnt before.
In my experience, the stopcock should be one turn short of fully open. That might not suit all houses, but its never caused a problem for me, and i
leave them like that every week.
quote:
Originally posted by JoelP
In my experience, the stopcock should be one turn short of fully open. That might not suit all houses, but its never caused a problem for me, and i leave them like that every week.
yup, the one turn short just stops it siezeing. Ie, full flow from me! 
It was an old time plumber who told me. Turn the kitchen tap on then open the stop cock, if the water hits the floor, back it off or at some time you
will look like you've p!ssed yourself. 