On Wed, 14 Jul 2010 18:48:34 +0100, "The Medway Handyman"
wrote:

MM wrote:
On Tue, 13 Jul 2010 22:30:38 +0100, "The Medway Handyman"
wrote:

MM wrote:
My low-level cistern has a button to press to flush the loo. If I
simply press the button I get water hammer noise. If I press it
initially very gently, so as to release some water into the bowl,
and then press fully down, I DON'T get water hammer.

So where is the *actual* water hammer noise emanating from? I've
read before that water hammer is something to do with high pressure
and valves, but I don't get how this only started recently (over
the past couple of months).

This is the cistern internal 'gubbins':
http://www.littletyke.myzen.co.uk/cistern/index.html

Its nothing to do with the bit you photographed - thats the flush
valve. Its the other bit with the blue float.

Is the water inlet plumbed in copper or is there a SS braided
flexible?

Plumbed in copper. With an inline shut-off valve (screwdriver slot)
almost directly beneath the cistern.

Try turning that down a bit.

I did a few weeks ago. Made an initial difference, but now the
hammering is back. However, I'm sure the diagnosis of the diaphragm
being at fault is correct, since when I (lid off) depress the float
arm ~~~very~~~ slightly, the hammering is immediate and one can almost
see the plastic boss on which it is mounted vibrating a bit.

Trouble is, I have scoured the internet (Screwfix, Plumb Center etc)
and have so far failed to find any replacement diaphragm. Maybe the
whole unit will have to be replaced, which would be no big deal since
a bottom-fitting one is only £3.99 at Screwfix.

MM