Domoticz

Hi
I've assembled and tested a different than OTGW hardware for opentherm boiler control.
Shop and additional info available here: Domoticz OpenTherm Thermostat.
They has a few other integration samples as well as gateway or OT slave setup, so it can coexist with already installed wall units.
For just a thermostat or boiler remote controlling build is pretty straightforward, you just need to connect OT shield to the boiler and flash example sketch into ESP8266/ESP32 board.
Connection overview:

Skect is on github repo.
That product is quite new and authors are maintaining it, so we can request some features.

i used this hardware as well, works quite well, so i created a domoticz python plugin and alternative firmware (sketch) to make it suit my needs (a weather dependent heating system or a "weersafhankelijke regeling" as we say in dutch )

details can be found here: viewtopic.php?f=34&t=36367

(PS i saw your post after i made mine, otherwise i would probably not have created another thread, but put the info in here as a response in this thread)