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Does OTGW need OpenTherm on thermstat and CV?

Posted: Monday 19 June 2017 9:49
by Hobbybob
I'm looking around for a new CV, and of course integrating this with Domoticz. OpenTherm is the obvious way to go, and I have found a couple of CV's that would work really well.

At this moment I have a non-OpenTherm thermostat in the living room that I am very content with. This one also works with the CV's I am looking at.

My question is: does the OTGW need to be connected to the thermostat through OpenTherm also, or does it work when OTGW can "talk" with the CV, that in turn communicates with the thermostat in its own propitiatory language?

Re: Does OTGW need OpenTherm on thermstat and CV?

Posted: Thursday 06 July 2017 10:10
by stlaha2007
Simply said, OTGW sits between the thermostat and CV talking OpenTherm.

There are systems with other protocols eg. Nefit that also have OpenTherm connectors.

The OTGW can work without a thermostat connected to it. Have read the otgw-site several times, and it is not recommended to use Only the OTGW (without thermostat), but can be done.

It's up to the CV-system if it's capable of being controlled by two devices acting as 'Thermostats' through two protocols. Most CV-systems i know only like one or like a multiroom system as Honeywell's EvoHome.

Sent from my D6603 using Tapatalk

Re: Does OTGW need OpenTherm on thermstat and CV?

Posted: Thursday 06 July 2017 10:44
by Hobbybob
stlaha2007 wrote:Simply said, OTGW sits between the thermostat and CV talking OpenTherm.

There are systems with other protocols eg. Nefit that also have OpenTherm connectors.

The OTGW can work without a thermostat connected to it. Have read the otgw-site several times, and it is not recommended to use Only the OTGW (without thermostat), but can be done.

It's up to the CV-system if it's capable of being controlled by two devices acting as 'Thermostats' through two protocols. Most CV-systems i know only like one or like a multiroom system as Honeywell's EvoHome.

Sent from my D6603 using Tapatalk
Okay, thanks for the explanation!

Re: Does OTGW need OpenTherm on thermstat and CV?

Posted: Thursday 10 May 2018 22:47
by MaikelK
I have a similar question.
I am now controlling my old CV unit with on/off control vi a relay box of the Evohome.
Im very pleased with the control and we have low temperature heating(floorheating).

Our CV is 20 years old, im guessing it will breakdown sooner then later and am searching for a new CV and to integrate its performance data etc into Domoticz.

Can is use the OTGW for only reading data and use the relay to turn the CV on and off?

Re: Does OTGW need OpenTherm on thermstat and CV?

Posted: Thursday 04 July 2019 7:38
by Domotibart
Hi,

I just found this solution. I think this is just what you are looking for. I am currently using the OTGW but this looks very interesting.
http://ihormelnyk.com/opentherm_thermostat

Bart