Which smart thermostat for Vaillant Ecotec 831 plus?

[chaosphere]

I’ll try to keep this as short as possible!

Basically the timer has died on my Ecotec plus 831 combi and rather than just replace it with similar I was thinking now maybe the time to go smart and get something that can help my heating system run more economically as we’re off grid so run off LPG which costs a packet.

I was thinking of hive or nest etc but I saw YouTube video explaining about boiler modulation and load compensation which is something not all smart thermostats offer. Then there’s smart TRVs to think about...I just don’t really know if this will give me savings worth the investment needed or even which one to buy.

Setup is as follows:

Ecotec plus 831 combi (5/6 years old serviced yearly)
Time switch 150 (not programmable, the dial with pins jobby)
Siemens RDH10RF wireless thermostat
13 radiators all with numbered TRVs (ones in use set to 3/2, other set to frost)
Radiator temp 70, Water 60
Usually thermostat set to 19.5

Any advice would be greatly appreciated, in way over my head here!

 

[picasso]

Any of the standard "smart" stats will work with your combi, vaillant dont support opentherm so thats a non starter, evohome is also good but maybe overkill for your system unless you have deep pockets.