On Sat, 16 Feb 2013 13:34:38 -0000, "Dave West"
wrote:

We have a bedroom radiator that we occasionally want to turn right down. It
has 'tamper-proof' caps on the valves at each end. So I will replace one cap
with a new one that easily allows the turning of the valve.

Is it advisable to put the new cap on either the water incoming end or the
water outgoing end of the radiator?


It makes little difference so put it on the side where it is more
convenient.

Have you soured a suitable wheel-head cap yet, they are not as easy as
you might think to find, and the spindle size varies.
This site might be useful

http://www.radcaps.co.uk/