In an earlier contribution to this discussion,
wrote:
Hi


I need isolating valves for the CH so I can take rads off and still
run the rest. I've got 15mm or half inch copper, little room to play
with, and 2-3m of pipe will be hanging off the valves in some
locations, so I'm thinking compression rather than pushfit.
Compression would also make reassembly easier, with egtting
everything lined up.

I ask cos Ive heard there are issues with full flow or not - which of
the following screwfixes ok for CH? Whats the difference? I know
diddly about water valves.

13483 79p p290 (I see they have an arrow on, I dont know which way the
water flows).

17447 £1.20 p290

18796 2.29 p291

19933 2.29 p291

21860 3.19 p291

http://www.screwfix.com/


thanks,
NT

Only the very last of your examples is full bore. You can tell because it
says so(!) and because it is very much fatter in the ball area - allowing
space for a big enough ball to have a 13mm or so hole through it.

Whether or not it matters depends on the size of radiator. The others are
likely to have a bore in the region of 6-8mm - which is ok for small to
moderate rads, but too restrictive for large ones.

It's easy enough to determine flow direction. Water flows *into* the
radiator through the hotter pipe and *out* through the cooler pipe.
--
Cheers,
Set Square