Otgw and Remeha tzerra ace with etwist thermostat

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Templar
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Re: Otgw and Remeha tzerra ace with etwist thermostat

Post by Templar »

Willem wrote:The Remeha Tzerra Ace boiler has what they call an R-bus. This bus should be capable, according to the documentation, of running the OT protocol as well as some kind of specific Remeha protocol. The E-twist thermostat should also be able to talk Opentherm.
I have the Nodo shop opentherm gateway running and connected via Wifi to Openhab with the OpenTherm gateway binding installed, so far so good everything comes online as it should.
At the gateway side things are a bit more problematic. With only the thermostat connected and the reference set to 1.25V I am only seeing error 3 messages in the terminal and the thermostat does not connect.
When 1 set the reference to voltage to 0.625V (0) the error 3 message disappears and the thermostat keeps connecting disconnecting.
I am running version 4.2.5 firmwater.
I hooked up a scope to the Ot bus and that seems to look fine I have a base line of 6 volt and on that I have 10 volt pulses.
The thermostat sends out first 9 bits then a 6mSec pause followed by 18 bits this is then repeated every 500 mSec.

With nothing connected the gateway is sending out the following messages:
17:10:38.761797 R00000000 Read-Data Status: 00000000 00000000
- CH enable: disabled (0)
- DHW enable: disabled (0)
- Cooling enable: disabled (0)
- OTC active: not active (0)
- CH2 enable: disabled (0)
- Summer/winter mode: winter (0)
- DHW blocking: unblocked (0)
I found nothing on-line about connecting the Tzerra ace (new version of the Tzerra plus) with Etwist to the openhab gateway so I might be the first to try this.
I am a bit stuck at this moment and was hoping that somebody could help me forward.
Kind regards Willem
In the eTwist manual I am reading that you need a Remeha Gateway if your boiler doesn't use the R-busprotocol. You must use the Gateway 16 if you're using a on/off or an OpenTherm thermostat and a Gateway 17 if your thermostat supports the BSB-protocol. So I guess the eTwist doesn't support OT.

tools.remeha.nl/veelgestelde-vragen/wan ... way-nodig/
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Re: Otgw and Remeha tzerra ace with etwist thermostat

Post by hvxl »

You did not provide details on how you tried the setup of etwist and OTGW and what the OTGW reported. Try setting the OTGW to monitor mode. That will forward all opentherm level signals from one interface to the other. If nothing works in that mode, the devices are using a different physical layer and that configuration is just not going to work. If the thermostat and boiler start communicating, even if the OTGW only reports errors, you may just need to apply the firmware modification mentioned earlier.
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Re: Otgw and Remeha tzerra ace with etwist thermostat

Post by sincze »

hvxl wrote:You did not provide details on how you tried the setup of etwist and OTGW and what the OTGW reported. Try setting the OTGW to monitor mode. That will forward all opentherm level signals from one interface to the other. If nothing works in that mode, the devices are using a different physical layer and that configuration is just not going to work. If the thermostat and boiler start communicating, even if the OTGW only reports errors, you may just need to apply the firmware modification mentioned earlier.
True I only connected it to the OTGW. DId not switch to monitor mode indeed.
However after that I stopped the investigation to prevent breaking my precious OTGW after I found
gathering.tweakers.net/forum/list_messa ... 0#60610650
ketel > OTGW > eTwist, werkt dan natuurlijk niet omdat de eTwist verwacht dat hij met die rbus kan praten. En dat snapt de OTGW natuurlijk niet. Dus of een gateway er tussen, of gewoon de iSense houden en "ketel > OTGW > iSense doen.
it's a bit unclear if
BOILER -> OTGW -> etwist (Remeha RU2 HW Version 7 /HW v1.07) should actually work due to etwist 'speaking' RBUS. however I did find.
gathering.tweakers.net/forum/list_messa ... 0#60126750
ik heb het even voor je getest het werkt deels
je moet ook de e-twist gateway gebruiken,
de otgw moet dan tussen de gateway en de cv ketel, als je Remeha Ace ketel hebt heb je waarschijnlijk geen gateway en communiceerd de thermostaat rechtstreeks met de ketel via het Rbus protocol dit werkt niet met de otgw.

als je de gateway er tussenplaatst kan je wel de cv uitlezen maar niet de temperatuur overrullen
Bit of a shame of this thermostat if temperature cannot be overruled. Seems this thermostat is able to set and extract some values from the boiler that are not communicated via OT.
etwist.PNG
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