John Rumm wrote:

Terry Pinnell wrote:

I have just noticed that, after running water, there is a lot of noisy
'hissing' as tank refills. Seems to be coming from all pipes en route
to the tank and at the valve itself. Definitely wasn't that high
pitched noise before. What is likely cause of that please? Sounds sort
of like air in the pipes.

Sounds like what they call "water hammer", probably just a function of
high pressure water through a different type of ball valve.

No hammering or oscillation, just the very noticeable 'whooshing'.

It does not indicate a problem as such and may just be an indication that the tank
is refilling faster than before.

If the noise is a problem, then you would have to consider changing the
valve for a different design, or perhaps adjusting the flow rate to it
with the addition of a stop valve in-line with it.

For £75 (15 mins work, with me as unpaid assistant!) I expect it to be
done properly, so I've called the plumber back.

--
Terry, West Sussex, UK