My combi boiler understands all the OT commands issued by the thermostat, but the stat doesn't request the return water temperature. I sacrificed the water pressure request as a UI to get a slot, and added the return water temperature as an AA, and all is good.
If I add a new AA parameter (DHW flow, for example), will the OTGW cycle through the AA parameters giving me both return temp and DHW flow (obviously reporting at half the update rate)?
And the final weird one- if I add the water pressure back as an AA, along with the others above, will it start reporting the water pressure again, along with the return temp and DHW flow, even though the water pressure was defined as a UI. I understand the pressure reading won't be returned back to the stat.
So:
UI=18 # Mark water pressure request from stat as not supported
AA=28 # Request return water temp in the pressure slot
AA=19 # Request DHW flow in the pressure slot
AA=18 # Request water pressure again in the pressure slot
(Cant actually try this on the board, as I don't have access at the moment, hence the question here)
Multiple Add Alternative associated with single Unknown ID
Moderator: hvxl
Re: Multiple Add Alternative associated with single Unknown ID
You are correct about the first part. There is no fixed mapping from an alternative to a specific available slot. Each available slot is used by the next ID on the list of alternatives. If there is only one unknown ID in the cycle of messages the thermostat requests and there are two alternatives defined, the available slot in the first cycle is used to send the first alternative to the boiler. On the second cycle the second alternative is inserted.
If you mark ID18 as unknown, then add it as an alternative, the OTGW will send it when its turn comes, find that the boiler supports it and mark it as known again. So that won't work.
But is there really no other ID you can sacrifice? As the web site says, usually the room setpoint (ID16) and room temperature (ID24) are good candidates. Some people are hesitant to use those because they still want to see that information. That's fine, the OTGW will still receive the messages from the thermostat so you can see them. They are just not forwarded to the boiler. In general, a boiler should not need this information. It is supposed to base its heating operation on ID0, ID1, ID14, and ID25
If you mark ID18 as unknown, then add it as an alternative, the OTGW will send it when its turn comes, find that the boiler supports it and mark it as known again. So that won't work.
But is there really no other ID you can sacrifice? As the web site says, usually the room setpoint (ID16) and room temperature (ID24) are good candidates. Some people are hesitant to use those because they still want to see that information. That's fine, the OTGW will still receive the messages from the thermostat so you can see them. They are just not forwarded to the boiler. In general, a boiler should not need this information. It is supposed to base its heating operation on ID0, ID1, ID14, and ID25
Schelte
Re: Multiple Add Alternative associated with single Unknown ID
From the statistics tab on the OT monitor, I don't see any appearance of ID16 or 24.
The only strange one is ID14 (Write max relative modulation level), which gets a Unk response. Not sure what this does, but can a write be marked as an unknown ID and substituted with an AA?
The only strange one is ID14 (Write max relative modulation level), which gets a Unk response. Not sure what this does, but can a write be marked as an unknown ID and substituted with an AA?
Re: Multiple Add Alternative associated with single Unknown ID
Then you must have one of the few horrible thermostats that don't send the room temperature and room setpoint.
ID14 is mandatory. A boiler must respond with a Write-Ack. Yours doesn't, which is a violation of the Opentherm spec.
You really managed to get yourself a combination of inferior equipment.
Normally the OTGW will automatically mark a message that gets Unknown-DataID responses as unknown. But because ID14 is a mandatory message, the OTGW will refuse to blacklist it. Marking it as unknown with the UI command will not work either.
ID14 is mandatory. A boiler must respond with a Write-Ack. Yours doesn't, which is a violation of the Opentherm spec.
You really managed to get yourself a combination of inferior equipment.
Normally the OTGW will automatically mark a message that gets Unknown-DataID responses as unknown. But because ID14 is a mandatory message, the OTGW will refuse to blacklist it. Marking it as unknown with the UI command will not work either.
Schelte
Re: Multiple Add Alternative associated with single Unknown ID
Interesting about the ID14. I uploaded the boiler log (Vokera Linea One) to the OTGW site, and just checking it now I see that ID14 is a blank- strangely not an X, as it is returning a Unk-DataId. I might re-run the capability log again.
I'm guessing the WundaSmart HubSwitch, which is the source of the OT messages in my case, isn't sending a room temperature as it is controlling multiple zones, each with its own temperature and valve. There isn't one room temperature or setpoint to send.
I think I can sacrifice the DHW flow rate after all, so I'll switch the return water temp to that, and reinstate the water pressure.
Thanks for your help throughout (and over Christmas, too!).
I'm guessing the WundaSmart HubSwitch, which is the source of the OT messages in my case, isn't sending a room temperature as it is controlling multiple zones, each with its own temperature and valve. There isn't one room temperature or setpoint to send.
I think I can sacrifice the DHW flow rate after all, so I'll switch the return water temp to that, and reinstate the water pressure.
Thanks for your help throughout (and over Christmas, too!).
Re: Multiple Add Alternative associated with single Unknown ID
I don't see your log file. I'm afraid the upload may have failed because the previous user who uploaded a log for the Vokera Linea One added a space at the end of the name. I removed the space from the database and updated the tools to better cope with trailing whitespace. This is probably also why you don't see an x for ID14: The thermostat the other user used to create the log didn't request ID14.
Schelte
Re: Multiple Add Alternative associated with single Unknown ID
Ah, thanks for fixing the log. It was probably me that uploaded the previous one, which had the Vokera BeSmart wireless thermostat and hub 
I tried to get the capability log again, with the same boiler but the WundaSmart HubSwitch.
It seemed to get stuck in a loop Reading ID12 then Reading 13.0 then finally (wasn't watching it) it showed communication lost.
But this is drifting off the original question, which I think you have comprehensively answered!
I'll raise a separate query about this if it hasn't already been covered.
I tried to get the capability log again, with the same boiler but the WundaSmart HubSwitch.
It seemed to get stuck in a loop Reading ID12 then Reading 13.0 then finally (wasn't watching it) it showed communication lost.
But this is drifting off the original question, which I think you have comprehensively answered!
I'll raise a separate query about this if it hasn't already been covered.