How can I use Tado valves on all radiators?
I just installed the Tado V3+ starter kit with a single radiator valve to try out the system. My plan is to go for a couple more rooms next and then if all is well the whole house:
Boiler: Potterton Powermax HE Store - boiler with built in hot water tank. Timer for heating and hot water on the front of the boiler.
Hall: simple dial thermostat on the wall (no timer), radiator with no TRV
Other rooms: 14 additional radiators with TRVs (lounge and master bedroom have 2 each)
I have seen questions raised about if it's possible/safe to have Tado valves on every single radiator, but ideally I would like to achieve that. (For example this topic: https://community.tado.com/en-gb/discussion/2555/is-there-a-scenario-where-the-boiler-will-fire-with-all-trvs-closed.)
My only point of reference is my last house which had Honeywell Evohome. The system was professionally installed and had a controller wired to the boiler. If one or more of the TRVs wanted heat, the boiler came on. If none of them wanted heat, the boiler switched off. There was no central or room thermostat, just the ones on the radiators (7 in total).
How can I get this behaviour with Tado?
I don't mind paying the local plumbing firm to wire something up to the boiler - but what, and will it be compatible? The Extension Kit comes to mind, will it work here and ensure the boiler only comes on when needed?
Alternatively, will installing a thermostat in the hall help? I'm wondering if replacing the hard-wired dial thermostat with the Tado thermostat will ensure that the boiler only switches on if at least one radiator is calling for heat. I don't actually need a thermostat in the hall otherwise - the TRV one will suffice.
Also, as there is no TRV on the radiator at all in the hall, can one be fitted or do I need a new radiator? If I understand correctly, the thing Tado supplies is really just the head that pushes down on a pin in the valve that's already on the radiator. My hall radiator has a white cap on each end but when I take these off there's no pin to push down.
What I really do want is for the hall radiator not to be constantly on as it is now - it's next to the front door and if the adjoining rooms are set to 22, I'd be happy to have the hall at 20.
In short - once all the other 14 radiators have TRVs, to finish the job: Extension Kit, wall thermostat or live with an over-heated hall?