"a" wrote in
:

such choice - is it just personal preference or are some types more
suited than others for certain applications? I have always liked ball
valves for their ease and speed of operation, but I need to
add/replace some valves and wondered if ball is the way to go here
(all 15mm copper pipe)

I would always fit full bore ball valves from new, and always replace
stopcocks and gate valves with them when replacemnent is required; and
replace with them right away in flow critical areas.

Recently on advice from here (maybe Andy, I can't recomember) I put a 22mm
full bore lever valve in the feed to my new HW cylinder.

It stayed for weeks with the cold tank full, and no pipe connected, and
didn't lose a drop; no gate valve would do that.

When I'd finished and opened it the flow was scary! It beat the mains
supply to the cold tank by gallons.

mike