I am looking for a way to either have a smart thermostat replace my current one (2 pin thermostat) or find a “smart bypass” to use near boiler. Main goal is to set it up to turn heating before waking hours and (if possible to control heating at will from smartphone for example to turn it all when leaving work).

I have found this solution that looks exactly like what I have: Honeywell T87RF2059 but with added connectivity. Not sure if this would do the trick since it mentions use with other controlers but anyway, I am looking for cheaper options if it is possible. Otherwise will buy this one provided it works for intended purpose.

Requirements are that I won’t run new wiring and will use the ones available at my living room location (three wires, one disconnected, one power (12/24/48v (will measure if needed)?, and one “signal return”). Can set up AC connection and new wiring in boiler room but don’t want it to somehow overlap/interfere with the option already set up (by way of living room no longer turning boiler on if house is too cold).

My little understanding of electrical connections tells me I should be able to set up a “smart switch” and have parallel connections in the boiler room. However I am not aware of any “over the counter” solutions (besides a chinese smart controller which I will only use as a smart switch?) and am a bit scared of the possible (?) reverse current on the current living room controller.

Hope you can provide your input! :)