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Open Therm Gateway PCB in parallel over the PCB of the Evohome

Posted: Wed Mar 13, 2024 9:14 am
by sipke@sipkew.eu
I heard on a Homey forum that an Open Therm Gateway kit can be used to read information from the high-efficiency boiler via the Open Therm protocol. This could be done using a Homey Pro 2023.

I have an Evohome thermostat with HR92 heads on the radiators in use and they also use the Open Therm protocol to control my heater.
Question: Can I connect an Open Therm Gateway PCB in parallel over the PCB of the Evohome from Honeywell. So putting both into use at the same time?

Would love to hear from you guys. Thanks in advance.

Greetings,
Sipke.

Re: Open Therm Gateway PCB in parallel over the PCB of the Evohome

Posted: Wed Mar 13, 2024 1:51 pm
by hvxl
Opentherm is a point to point protocol. So you cannot connect things in parallel. But you can use both an Opentherm thermostat and the OTGW by connecting them in series. In case of the Evohome thermostat that means: Connect the cable from the boiler to the boiler connector of the OTGW. Then connect the OTGW thermostat connector to the R8810 module of the Evohome system.

Re: Open Therm Gateway PCB in parallel over the PCB of the Evohome

Posted: Wed Mar 13, 2024 10:40 pm
by sipke@sipkew.eu
Good evening,
Top, thank you for your response. I will definitely try that out. At least then I can read the central heating boiler. Thanks again.
Greetings, Sipke.