After several tests, I have come to the conclusion that the master/slave mode, although correct, makes the operation of the boiler unpredictable (at least in my case).
The repeater mode with the overrides set to false does not interfere with the normal operation of the boiler but does not return all the operating values of the boiler (supply temperature, return temperature, circuit pressure, etc.).
So in my case, for the purpose for which I had purchased the device (monitoring the boiler’s parameters), the device is useless.
This is clear. If the roomunit does not ask for a value, OTthing can’t display it. You were writing about unpredictable behaviour in master/slave mode. What is it about?
Could be the case that only the flowtemperature is overriden, not the on/off bit. I will check.
This is correct. I’ve noticed that if I open the parameters view page from the room unit, parameters are reported statically (they don’t change over time, and the value displayed is the one at the time of reading).
Obout unpredictable bahaviour in master/slave mode I try to explain.
My setup is a bit complicated.
The boiler is connected to its roomunit which is used only for parameter settings (thermostat function disabled).
The boiler has been configured so that ignition control is via a NEST thermostat whose dry contact is connected directly to a boiler input (It is a possibility allowed by the manufacturer).
It’s not easy to explain the unpredictability I’m experiencing.
When configuring the otthings interface in master/slave mode with ovverides set to false (I was thinking to set the flow temperature based on the outside temperature), if the climate.otthing_flow_temperature entity (HA) is OFF when the whole system is turned on, I can’t control the flow temperature with OTC curve. However, if the climate.otthing_flow_temperature entity is set to AUTO, I can control the flow temperature with OTC. The boiler flame turns on and off correctly with the NEST thermostat, but the water circulation pump remains permanently on. After this step, if I switch the climate.otthing_flow_temperature entity back to OFF, I can still control the flow temperature with OTC and the boiler works correctly (also the water circulation pump). All this until the next system reboot where to take again the control I have to change the state of the climate to OFF then AUTO and then OFF again (however, in some cases it happened that the water circulation pump is ON regardless of the status of the climate control unit).
So I’m little bit confused.
Thank you for your explanation! Which parameters do you want to use from the roomunit? And which, if any, parameters of the OTThing do you want to be used for the slave?
I am currently using a tado wireless receiver x (didn’t know it was hard closed on cloud, I migrated almost everything locally - tado trvs, temp sensors etc) wired to the boiler in OT mode, and was looking for alternatives for the next season, but better to prepare and test from now.
Asked claude, told me my boiler should work with yours, can you maybe confirm it should work?
Its a viessmann Vitodens 100W B1KG, not exactly listed but it’s the same generation/family as the B1HC and B1KC entries that are confirmed working on github.
Last question, my Vitodens provide bus power, so no separate PSU required, right? I will I just remove the 2 ot wires from tado coming from the boiler OT terminals and wire to OT-Thing, done, right?
Thank you, will order now.
LE: could you please check why the shipping is so steep for a DHL EU delivery?
17,50 € via DHL Paket EU
I can not promise, but Vitodens 100W B1KG should word.
Yes, simply connect the 2 wires of your boiler to the clamps of the OTthing. In any case you will need an USB supply as the boiler cannot supply enough power for it.
Hallo Mirino75. Can you tell me about your Geminox , QAA73 and Home Assistant? How it work together ?
I have Geminox THRi and QAA73 too. I am considering zone control of radiator heating via Home Assistant. Is this realistic and possible?
Thank you.
Jan - Košice SK
Hi Stefan,
Sorry for the delay in responding, but I was abroad and didn’t have access to my PC.
What I need is for the OTThing interface to compensate only the flow temperature based on the external temperature (OTC), leaving all the rest of the control to the room unit and the boiler (the boiler has no external temperature sensor connected).
the OTC switch does not do anything in your case, switch on the override CH1 flow switch and OTthing should change the flowtemperature of the boiler according to the heatingcurve everytime your thermostat sends a set flow message.
