In an earlier contribution to this discussion,
TheScullster wrote:

"Andrew Gabriel" wrote

Also they present less of an inherent flow restriction.

although in this case, it's there for flow restriction!

--
True, but the reduced bore ball valves for instance present an
"inherent" flow restriction before you start throttling. So the
control offered will be over a smaller range. Yes I know the purists
will say that ball valves shouldn't be used for flow control!

Phil

I would be inclined to replace a short section of the 22mm pipe with 15mm
(with suitable reducing fittings) and with a 15mm gate valve in the 15mm
section. The smaller pipe *may* provide enough restriction on its own, but
the gate valve would provide additional fine tuning.
--
Cheers,
Roger
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