On Feb 16, 1:34*pm, "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 is probably a heat sink and has these valves fitted so it can't be
turned off.
Really you shouldn't mess with it.