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Opentherm Thermostat

Posted: Thu Oct 13, 2016 2:55 pm
by lifer
Hi,

I thought about building an Opentherm gateway at first but then I realized that it might worth to add some more functionality (by incorporating a temperature sensor and some logic) to act like a standalone thermostat, too.

That's it, by reading the boiler parameters (in gateway mode), I could make use of instant flow/return temperatures and by logging the room temperature versus time (and setpoint / modulation level) I could compute a heating/coo!ing curve for my house.

I want to use an Arduino and a ESP8266 wifi board to get wireless functionality. I could further add various RF sensor nodes for outside and zone temp sensors.

Does anyone built/start such a project, to not reinvent the wheel? I've read and searched a lot but I didn't found anything.

Thanks in advance for any clue.

Re: Opentherm Thermostat

Posted: Fri Oct 23, 2020 1:02 pm
by Rokite66
I am looking for the same thing. I have everything built, connected and working (opentherm gateway connected to boiler and homeseer PC, wireless temperature sensor inside and outside). Also I do not want to reinvent the wheel. What I need is an example of how to combine: inside temperature, requested inside teperature, outside temperature to control the boiler water temperature. I have also looked everywhere but all I can find is that it is not easy and that you need to implement a PID loop. Hope someone can point us in the right direction.