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Can we connect 2 room devices?

Posted: Thu Feb 14, 2019 8:26 pm
by jacques26
Hello everyone

I currently connected to my boiler a room controller
I found it under 2 different names.

QAA73
https://www.iso-chauffe.com/Files/27354 ... 556615.pdf
and
REG 73
http://fr.documents.bosch-climate.com/d ... 801001.pdf

I would like to connect an opentherm card : http://otgw.tclcode.com/ to remotely control my heating and adjust the temperature of the house.

I wonder.
Is it possible to put in parallel the opentherm card and the controller?

If yes, how ?
Is there a protection between the two?

thank you in advance for your help
And sorry for my bad english
Jacques

Re: Can we connect 2 room devices?

Posted: Tue Feb 19, 2019 9:14 pm
by hvxl
No, you can't connect two Opentherm devices in parallel. Opentherm works with a point-to-point connection. But the two devices you ask about are a thermostat and an OTGW. The OTGW has been designed so that it can be used together with a thermostat. You connect the thermostat to the OTGW and then connect the OTGW to the boiler. This way the OTGW sits between the thermostat and the boiler. It normally forwards messages between the two endpoints. It only modifies the odd message, if instructed to do something special.

Re: Can we connect 2 room devices?

Posted: Sun Feb 24, 2019 11:45 pm
by jacques26
Hello
Thank you for this return, if I understand correctly, this is not good News! :x


The current QAA73 is in the living room and I want to put the OTGW on the second floor!

On the OTGW I do not have a thermostat!
I was thinking of using the one in room device one.

So that's not possible either?

There is really no way to send information via the OTGW and view them on the room device?

At worst, how can the person at the show recover the information?

I hope I'm clear!
Jacques

Re: Can we connect 2 room devices?

Posted: Mon Mar 04, 2019 10:28 pm
by hvxl
The location of the devices doesn't really matter much, as long as you connect the thermostat to the OTGW and then connect the OTGW to the boiler. According to the specs, Opentherm connections may be up to 50 meters long (although I have to admit that I haven't tested if that works with the OTGW). My own OTGW does have several meters of cable on both sides; toward the thermostat as well as the boiler. That works fine.