On Tue, 23 Sep 2003 12:38:48 +0000 (UTC), wrote:

But will that have a different effect to partially closing the
service valve ?

Donno try it. Easy enough to do...

As I said, to stop the noise I have to reduce the flow rate so far
that the fill time is unacceptable (longer than the original
ball cock, which defeats the object).

Apart from the noise most ball cocks make, though I suspect your old
ballcock may have been a low pressure one rather than high pressure
so probably not very noisy anyway.

I'll try the restrictor if you think it will stop the bang at a
higher flow rate, but I can't really see why it should.

Fluid dynamics is complicated. The flow restrictor will add a
significant amount of turbulance to the flow rather than just make the
hole through which the water has to pass smaller.

Nobody has commented on my observation that dismantling and
re-assembling the valve provides total relief from the bang for
about a day, before it gradually returns.

Presumably it's just that parts settling down into their correct
operating positions and possibly any air finally being purged out.

--
Cheers
Dave. pam is missing e-mail