On Fri, 27 Sep 2019 17:46:51 +0100, The Natural Philosopher
wrote:

On 27/09/2019 17:38, AnthonyL wrote:
I think the penny is dropping slowly. There are at least two types of
valve head. One which is purely mechanical so the user has to turn
the knob to allow more or less heat through the radiator. The other
is thermostatic so it attempts to stop the room from getting warmer
than it is set to. Is that right?
Yes. The latter is called a TRV, Thermostatic radiator valve.
In general a wax cylinder exapands and pushes the pin to cut off the rad
at a given point



Thanks, on my non-working one the cylinder does not change position as
I turn it. On a working one the cylinder does.

On the presumably non-thermostatic one the central pin is clearly on a
thread and just goes up and down with the rotation of the head.

I've not been careful enough about which type to select and which ones
are best installed in which rooms. With my new-found education I
shall save vasts amount of energy and help save the planet.


--
AnthonyL

Why do scientists need to BELIEVE in anything?