Opentherm Protocol Version 2018

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richardc1983
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Opentherm Protocol Version 2018

Post by richardc1983 »

Hey there,

My first post but a google search has led me here to this great forum resource.

I have a Ideal Vogue C32 boiler and a Nest Gen 3 but have also tried Honeywell Lyric T6. We having lots of issues with opentherm particularly around modulation and short cycling of the boiler at low loads.

We have been dealing with Ideal boilers directly within there R&D department very high up and they are now stating that they are planning on putting the latest version of opentherm onto the boiler as its still apparently running version 2.2.

Any ideas where I can find a spec sheet or change log that details through the versions of what has changed in opentherm?

Kind Regards
Richard.
Templar
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Re: Opentherm Protocol Version 2018

Post by Templar »

richardc1983 wrote:Hey there,

My first post but a google search has led me here to this great forum resource.

I have a Ideal Vogue C32 boiler and a Nest Gen 3 but have also tried Honeywell Lyric T6. We having lots of issues with opentherm particularly around modulation and short cycling of the boiler at low loads.

We have been dealing with Ideal boilers directly within there R&D department very high up and they are now stating that they are planning on putting the latest version of opentherm onto the boiler as its still apparently running version 2.2.

Any ideas where I can find a spec sheet or change log that details through the versions of what has changed in opentherm?

Kind Regards
Richard.
In this download there is a file called Data-Id Map.otm. It contains all the OpenTherm Technical Specifications v2.3b Data-ID's. And here you can find a file called otmonitor.tcl with additional info.
richardc1983
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Re: Opentherm Protocol Version 2018

Post by richardc1983 »

Thank you is v2. 3b the latest version they told me it was version 4?
Templar
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Re: Opentherm Protocol Version 2018

Post by Templar »

richardc1983 wrote:Thank you is v2. 3b the latest version they told me it was version 4?
I haven't heard of version 4. As far as I know the latest version is 3.0, with Smart Power, which is (partially) implemented in OpenTherm Gateway.
hvxl
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Re: Opentherm Protocol Version 2018

Post by hvxl »

Yes, version 4.0 is the latest. But unfortunately the specifications aren't made publicly available. So hobbyists have to make do with the documents that have escaped onto the internet. Newer versions of the specification usually only add new MsgIDs (or assign meaning to unused bits of existing MsgIDs). So the information in older specs remains largely valid.
Schelte
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Re: Opentherm Protocol Version 2018

Post by Templar »

According to this document from 2016 the OpenTherm Association is testing OT version 5.0.
OpenTherm-workshop-at-the-Mostra-Convegno-20161.pdf

Version history
20 years of protocol development:
–first official release : 1996-1997
–Version 2.0 : 2000
–Version 2.2 : 2003 (february 7)
–Version 3.0: 2006 (Smart power)
–Version 4.0: 2011 (may 12)

Version 5.0: Currently being tested
• Larger datapackages
• Addressing
• Slave-master communication

According to the document there are (or will be) 7 mandatory ID's.
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