Water hammer/low pressure

[wave]

Hi all,
We have recently had a new electric shower fitted. However since turning the water back on, there is a knocking sound (which I assume is water hammer) whenever we turn the kitchen tap off, but the shower pressure is fine. However if we turn the stop cock off slightly the hammer goes but the shower pressure is affected when toilets or taps are used...
Is this an easy fix?
Thanks

 

[Armo74]

Check all valves to see if any are dripping if one is then replace it. Failing that are any of your tap's dripping? If one is then replace washer/cartridge.

 

[Charnwood]

Is the shower a complete install or just a replacement shower on existing pipework?
If new pipework, is it fitted correctly, i.e. clipped properly and not loose?

Tell the installer that you've now got water hammer since he fitted the shower, which you never had before.

 

[wave]

Thanks for the replies
Yes it is a replacement shower (the same 8.5kw) on existing pipework, so I'm unsure if it is to do with this or not.

I am wondering if the problem might lay at our stop cock as there is a slight leak coming from it when it's slightly open, but fine when fully open, I asked a plumber and was told it is normal for stop cocks to leak slightly when not fully open(?!)

 

[Charnwood]

I asked a plumber and was told it is normal for stop cocks to leak slightly when not fully open(?!)

Codswallop!!!

 

[wave]

lol as I suspected

So, is fixing a stop cock an easy job for a novice?!

 

[Charnwood]

Leaking from where, the spindle?
Might just need repacking.

Three and a half minutes in:
http://www.youtube.com/watch?v=unOzP1GZwqI

(Thanks to Andy/Hertsdrainage2010.)

 

[raymondbowon]

A mini expansion vessel or shock arrester will cure the water hammer.

Cheap fix.

Jim

 

[raymondbowon]

One like this

http://compare.ebay.co.uk/like/2611...ixedPriceItemTypes&var=sbar&adtype=pla&crdt=0

 

[wave]

Sorry for the gap between posts, but just wanted to say thank you for the replies and to Charnwood/Andy for the vid link, that was very helpful and I tightened the gland nut which seems to have helped, I may still re-pack it though to be extra sure! Still need to sort the water hammer issue upstairs but I think that expansion vessel may just be what it needs, I don't know if that is something I dare attempt myself though..
Thanks again guys