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

MM

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

MM
The hammer will be coming from the fill valve. I expect pressing the
flush gently start the refill slowly rather than quickly when doing a
'fast' flush.
Maybe changing the diaphragm in the valve will shut it up.
Or fit a hammer suppressor in the pipe nearby.

Bob

On Tue, 13 Jul 2010 11:05:21 +0100, Bob Minchin
wrote:

The hammer will be coming from the fill valve. I expect pressing the
flush gently start the refill slowly rather than quickly when doing a
'fast' flush.
Maybe changing the diaphragm in the valve will shut it up.

Looking at the top picture at
http://www.littletyke.myzen.co.uk/cistern/index.html do you mean the
white component in the right corner (closest to tiles) on which the
ball valve arm is mounted? It has a cap of some kind with "teeth"
around the circumference. Presumably this can be unscrewed?

Or fit a hammer suppressor in the pipe nearby.

I could, but this hammering only started fairly recently, so something
must have happened to cause it, e.g. something or other worn after
five years' usage.

MM

MM wrote:
On Tue, 13 Jul 2010 11:05:21 +0100, Bob Minchin
wrote:

The hammer will be coming from the fill valve. I expect pressing the
flush gently start the refill slowly rather than quickly when doing a
'fast' flush.
Maybe changing the diaphragm in the valve will shut it up.

Looking at the top picture at
http://www.littletyke.myzen.co.uk/cistern/index.html do you mean the
white component in the right corner (closest to tiles) on which the
ball valve arm is mounted? It has a cap of some kind with "teeth"
around the circumference. Presumably this can be unscrewed?

Yes & yes. turn off the water first! note which way round the diaphragm
is fitted.

Or fit a hammer suppressor in the pipe nearby.

I could, but this hammering only started fairly recently, so something
must have happened to cause it, e.g. something or other worn after
five years' usage.

MM

Only bother to do this if the diaphragm change does not fix it.

Bob

On Tue, 13 Jul 2010 11:37:24 +0100, Bob Minchin
wrote:

MM wrote:
On Tue, 13 Jul 2010 11:05:21 +0100, Bob Minchin
wrote:

The hammer will be coming from the fill valve. I expect pressing the
flush gently start the refill slowly rather than quickly when doing a
'fast' flush.
Maybe changing the diaphragm in the valve will shut it up.

Looking at the top picture at
http://www.littletyke.myzen.co.uk/cistern/index.html do you mean the
white component in the right corner (closest to tiles) on which the
ball valve arm is mounted? It has a cap of some kind with "teeth"
around the circumference. Presumably this can be unscrewed?

Yes & yes. turn off the water first! note which way round the diaphragm
is fitted.

Or fit a hammer suppressor in the pipe nearby.

I could, but this hammering only started fairly recently, so something
must have happened to cause it, e.g. something or other worn after
five years' usage.

MM

Only bother to do this if the diaphragm change does not fix it.

I've had the lid off the top of the cistern and just realised that the
water hammer occurs AS SOON AS I depress the float arm, even by only a
tiny movement. Does that confirm your "diaphragm" diagnosis?

Thanks, BTW!

MM

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?


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk


MM

"MM" wrote in message
...
On Tue, 13 Jul 2010 11:37:24 +0100, Bob Minchin
wrote:

MM wrote:
On Tue, 13 Jul 2010 11:05:21 +0100, Bob Minchin
wrote:

The hammer will be coming from the fill valve. I expect pressing the
flush gently start the refill slowly rather than quickly when doing a
'fast' flush.
Maybe changing the diaphragm in the valve will shut it up.

Looking at the top picture at
http://www.littletyke.myzen.co.uk/cistern/index.html do you mean the
white component in the right corner (closest to tiles) on which the
ball valve arm is mounted? It has a cap of some kind with "teeth"
around the circumference. Presumably this can be unscrewed?

Yes & yes. turn off the water first! note which way round the diaphragm
is fitted.

Or fit a hammer suppressor in the pipe nearby.

I could, but this hammering only started fairly recently, so something
must have happened to cause it, e.g. something or other worn after
five years' usage.

MM

Only bother to do this if the diaphragm change does not fix it.

I've had the lid off the top of the cistern and just realised that the
water hammer occurs AS SOON AS I depress the float arm, even by only a
tiny movement. Does that confirm your "diaphragm" diagnosis?

Thanks, BTW!

MM

Seems to me your initial problem was waves/ripples joggling the float. It
may well go away if you lower the float a little so the water level pushes
it up more firmly.

S

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.

MM

"MM" wrote in message
...
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

MM

How is the adjustment on the screw thread holding the assembly away from the
side? If there's any movement, I could see that this may cause hammer from
interaction of the float arm and assembly.

On Jul 13, 9:37 pm, 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 the mains water pressure has increased recently that could cause a
problem. I have fitted a pressure reducng valve in my main pipe and
that has fixed all my plumbing problems.
Rubber diaphrams can cause hammer while fibre diaphrams won't.

On Jul 13, 10:37*am, 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

MM

http://wiki.diyfaq.org.uk/index.php?title=Noisy_Pipes

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.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

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

On Jul 15, 6:59*am, MM wrote:
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

any plumber's merchant should have a little rubber disc for it.
Replacement discs dont necssarily need to be of identical design.


NT

On Jul 15, 7:13 pm, NT wrote:

any plumber's merchant should have a little rubber disc for it.

Rubber disks cause water hammer. Fibre disks don'r.

On Thu, 15 Jul 2010 01:27:46 -0700 (PDT), Matty F
wrote:

On Jul 15, 7:13 pm, NT wrote:

any plumber's merchant should have a little rubber disc for it.

Rubber disks cause water hammer. Fibre disks don'r.

Doesn't the disk have a small hole in it to equalise pressure? That's
what I've read on one of the suppliers' sites.

MM

"Matty F" wrote in message
...
On Jul 15, 7:13 pm, NT wrote:

any plumber's merchant should have a little rubber disc for it.

Rubber disks cause water hammer. Fibre disks don'r.




Not sure you can get fibre ones for the type he illustrated with a photo. I
know you can use fibre on the old ball valves - but modern diaphragm ones
need the flexible walls of rubber. (surely)