On 08/10/2020 11:49, Roland Perry wrote:
Currently I have a boiler with a controller that simply turns it on (for
CH) during pre-programmed hours. Rads have thermostatic valves.

I'd like to add a room thermostat in the living room [running additional
wiring isn't an issue] but need to know if it can simply be put in
series with the timer-control.

I realise that the heat in the rest of the house will suffer if the
living room is warm enough, but surely that's a natural consequence of
any room thermostat.

Not quite the same, but I have a switch by the back door going to the
boiler "room thermostat" terminals that are normally shorted for
thermostatic rads. Electrically, it's doing what you propose.

I have this switch so that it is easy to turn the house off and on if it
is going to be empty for a few hours. I guess in the fullness of time I
might make this "remote actuated" but like you, I'm in favour of keeping
it simple.