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Directly control water temperature

PostPosted: Sun Apr 01, 2018 12:26 am
by Wavemaker
I have a set-up where all my heaters are equipped with Max EQ3 automatic thermostatic valves and I have the OTGW monitoring my Intergas Kombi Kompakt HRE A 28/24 boiler and Honewell Round Modulation thermostat. The temperature override is working properly.

The (obviously) Honeywell only controls the temperature in one location (the living room). I would like to let the OTGW control the boiler such that it keeps ALL rooms to their minimum temperature as set on the Max EQ3 units. And I would still like to use the Honeywell thermostat in the living room to control just the living room.

I understand this is not basic functionality of the OTGW. So I expect that I will need to write my own script with PID control to do this, to read time traces from influxdb and to control the OTGW through serial or MQTT.

But my main question is: are there any serial/MQTT commands/topics that I can already use to directly control the boiler water temperature? Where to make edits in the otmonitor code (if applicable). Did anybody do this before...?

Re: Directly control water temperature

PostPosted: Mon Apr 02, 2018 9:30 am
by hvxl
The serial commands to control the boiler water temperature have been available for a long time. Check out the CS, CH, and MM commands.

It wasn't yet possible to issue these commands through MQTT, so I have added some more actions to the OTmonitor source code. With this version, the available MQTT action topics are:
  • actions/otmonitor/setpoint (Temporarily change the thermostat setpoint)
  • actions/otmonitor/constant (Permanently change the thermostat setpoint)
  • actions/otmonitor/outside (Set outside temperature)
  • actions/otmonitor/hotwater (Domestic hot water enable)
  • actions/otmonitor/gatewaymode (Switch between gateway and monitor mode)
  • actions/otmonitor/setback (Configure the setback temperature)
  • actions/otmonitor/maxchsetpt (Set the maximum central heating setpoint)
  • actions/otmonitor/maxdhwsetpt (Set the domestic hot water setpoint)
  • actions/otmonitor/maxmodulation (Override the maximum relative modulation)
  • actions/otmonitor/ctrlsetpt (Override the control setpoint)
  • actions/otmonitor/chenable (Control the CH enable status bit)
  • actions/otmonitor/ventsetpt (Configure a ventilation setpoint override value)
Note: I also noticed that the code failed to correctly determine the data format and always interpreted the actions data as "unformatted". That has been fixed. So, if you have the data format set to one of the JSON flavors, you should now also send the data as JSON.

Re: Directly control water temperature

PostPosted: Wed Apr 04, 2018 11:46 pm
by Wavemaker
My bad, I never sufficiently looked at the total list of serial commands on the firmware page. Didn't expect it there... So yes, everything is there to get started and support from MQTT even makes things more elegant. Thanks for a great tool! I'll report here when I have things working (that may take a while).

Re: Directly control water temperature

PostPosted: Sun May 12, 2019 2:22 pm
by umtauscher
Hi hvxl,

thanks, thats exacly what I was searching for today.
Is there a binary for Raspberry Pi already built with the changes?
If I am correct, the last binary is older than the new additions?


Re: Directly control water temperature

PostPosted: Tue May 14, 2019 12:35 pm
by hvxl
Correct. If you want to have a single file executable containing the latest updates, you have to follow a few steps yourself to create the binary.