"IMM" wrote in message
...

"Bob Mannix" wrote in message
...

"Rod Hewitt" wrote in message
...
Well good ol' neighbours. They have a problem with their water supply.
Several times a day it makes an awful noise - trying to describe it I
came up with foghorn - but a bit higher pitched.


It's possibly the toilet filling. One of ours does the same from time to
time. The contributing factors a the age and stiffness of the
ball-valve
diphragm (worse when its older and stiffer - as the actress said to the
bishop), the presssure of the water (higher=worse) and the temperature
of
the water (colder=worse as the diaphragm gets stiffer) plus, of course,
the
resonant capability of the pipework. I changed the ball valve diaphragm
once
and it went away for a few months but comes back now when the conditions
are
right. It's only occasional now but I would probably add another pipe
bracket somewhere with a rubber sleeve next to change the resonant
frequency
of the pipes next if I could be *rsed.

You can generally stop it by opening a mains tap as this drops the
pressure
a bit - in fact you can tap out signals by turning it on and off if
you've
nothing better to do - try it with next door's!

Just fit a shock arrestor next to the ball valve and stop messing about.

Firstly, I'm not messing about (well, other than by posting a reply) - if
you read the text above you'll see I'm not doing anything, the severity of
the problem not warranting it!

Secondly, the shock arresters are for water hammer, which generally occurs
on tank/ball valve arrangements where the resonance occurs when the ball
float moves up and down due to water ingress which moves the valve causing a
spurt of water which causes the float to move etc., etc. or where pipes
feeding mains taps are loose. It is not clear to me that the shock arrester
would be effective for higher frequency resonances set up in
diaphragms/washers, whic arren't really "hammer". Using an electrical
analogy, the shock arrester adds a capacitive-resistive element to the
circuit. It's size and shape will determine the range of frequencies it
filters out.

Thirdly, they are reasonably sized devices and the area under the toilet
cistern inquestion is somewhat cramped so I probably couldn't get one in if
I wanted (at least, not neatly).


--
Bob Mannix