Graham wrote:

Thanks for the replies, They mostly confirmed my gut thoughts about the
matter.

One follow-up if I may?

What about radiator lockshield (and non-TRV) valves?
they are usually, if not always gate valves, and most of mine have weeping
steams if not kept fully open.
Are gate valves preferred for this application because they are better at
controlling the flow i.e. nether fully open nor closed?

Yup.

(You may be able to repack the valve gland with grease to stop them
weeping when partially open)

--
Cheers,

John.

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