On 08/11/2019 12:47, John Rumm wrote:
On 08/11/2019 10:16, wrote:
On Friday, November 8, 2019 at 10:12:17 AM UTC,
wrote:
Is the connection between a radiator tail and the actual valve any
sort of standard?

This bit is a stupid question isn't it. It must be either 3/4 or 1/2"
because why would anyone bother setting up for anything else.

Well its not as daft as it sounds...

The tail socket into the rad is almost always 1/2" BSP female. However
the other end of the tail varies. Traditionally it was a cone fitting
retained by a 3/4" BSP nut that was captive on the tail. However more
commonly these days the tail is often just a length of 15 mm pipe, and
the valve has a 15mm compression fitting that then connects to that
(ultimately leaving a 1/2" BSP not captive on the tail, but retained by
the olive rather than the cone fitting).


Definitely do not assume standard threads, you may have to remove the
fitting that goes into the radiator, rather than just swapping the
"valve" bit. This needs a big allen key and they are sometimes very
tight from corrosion. In my experience you can usually get away with the
slightly different dimensions by using the flexibility of the copper
pipes, provided they are not too constrained close to the radiator. One
of those jobs that usually takes longer than expected, IME.