On May 29, 11:32*am, Davey wrote:

I have just moved into a house fitted with these, Honeywell made. They
all seem to work more like a setting valve rather than as a thermostat.
Do I not need to drain any water, just undo the head somehow, and then
find a pin under there? I haven't tried anything yet, other things
need more attention!
--
Davey.

They are TRVs (thermostatic radiator valves).
Look em up on Google for all the tech data but they work like
individual thermostats for the temp around each rad... when they're
not sticking
Saves having a rad on in a room which is already warm, because the
room stat is located in the hallway, where it might be cooler!

deano.