Dave

Ah. I was assuming somewhere in the flat there is a thermostat that sets the overall temp, and TRVs in the rooms trim that. Commonly in the hallway.
Or have *all* rads got TRVs?

There is 1 thermostat near the living room. apart from that, i cant
find any in the flat.

But there is a thermostat on the cylinder
and i was told there should be another thermostat for the immersion
heater at the top of the cylinder - but i have not had a look at this
one yet.

No TRVs on any of my radiators.

after step 4), then thats it for me - nothing else
seems to happen.
why would having room one higher than ambient temp 'force' the motorised
valve to the heating position?


Only if you have a room stat somewhere - which is what your wiring diagram suggests.

ok - i do have a room stat.
so if 1 room is hotter than the others, the motorised valve should
cause the hot water to go down the 'central heating' pipe??

thanks
kiichi