Is there a reason you are not using a thermostat valve for the floor? Setups without a low heat loop make use of an thermostat set to around 22 for the floor. Or does the floor heating not has its own pump?
Iâm actually using thermostatic valve for floor heating, but this is only to keep floor circuit temp lower than radiators circuit. I guess this is a common solution for mixed heating solutions (floor heating and radiators). In addition to that, each floor heating loop have itâs own valve. I probably could use additional thermostats there but controlling them directly from Home Assistant makes much more sense for me. Probably there is a better way for âsmart heating solutionâ, but I spent quite a lot of time trying to figure out the best way of doing that on my installation and this is the best I could think of so far 
I send the alias command but it is not working. I added it under scripts:, should I do something else?
I do mine as a simple automation e.g.
alias: temp send
description: ''
trigger:
- platform: time_pattern
seconds: '20'
condition: []
action:
- service: mqtt.publish
data:
payload: '{{ states(''sensor.living_room_temperature'') }}'
topic: opentherm-thermostat/current-temperature/set
qos: 0
retain: 0
mode: single
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At the moment it works here already. thanks anyway
I notice, you use an automation to shut as well the pump as the boiler down from the moment that you reach a certain setting point. Since the water still holds energy, might it not be more interesting to let the pump work untill the water temperature drops below a certain value?
My combi boiler keeps the pump running until the water has dropped by 2 degrees. It does this when using a conventional thermostat, not open therm. So this is what the logic of the actual boiler does.
Iâm a perfect world the opentherm would turn off the boiler at 0.5c before the setpoint and then run only the pump to keep the radiators warm to raise that final bit of temperature.
But I imagine this would be problematic to implement. (better insulation = stopping the burner sooner before setpoint)
Hi Guys,
I am succeeding more and more with this installation, but I have a few more questions all related to one thing.
I use a bulex boiler, basically the same as AWB, Saunier-Duval, Vaillant with a VR33 circuit board to make the boiler able to communicate trough opetherm.
I donât receive a lot of information from the boiler:
Target boiler temperature is 0 degrees
Boiler temperature is 0 degrees
flame is always off
I read things that you can force the boiler to give that kind of information. With opentherm gateway they have AA=28 for example. Anyone knows if this is possible with the shield?
(google translate)
Thank you, currently everything is working OK, I am sending the current room temperature, I can set the hot water temperature (DHW) âŚ
I do not understand why the heating water (63 - boiler-target-temperature, 47 - boiler-temperature) is heated in this way, even if the difference between the temperature in the room set (22 - setpoint-temperature) and the current (21.5 - current-temperature) is minimum âŚ
When there is no heating demand (current-temperature> setpoint-temperature), then the boiler-temperature is around 35-38 degrees.
Lubo
Greetings to the community
It would be possible to add and obtain and display via HomeAssistant - lovelace also other data, which are named in the library OpenTherm.h - OpenThermMessageID:
- TOutside
- CHPressure
- DHWFlowRate
-Texhaust - HcratioUBHcratioLB
- HCratio - set the value of the heating curve?
- BurnerStarts and other statistics �
As I currently see e.g. Tboiler, Tdhw âŚ
Thank you, Ľubo
Built in PID algorithm will heat until room temp reaches or is more than setpoint. It takes into account speed of room heating and difference amount. And after room temp is >= 22°C boiler will not shut down but decrease temp until it finds a ballance between boiler temp and room following setpoint.
To shutdown boiler completely youâll need an external automation. You can use built in HA scripting or
node red for example.
@joparmen for extra parameters youâll need to modify a sketch. Burner stats are already published to mqtt (on/off and modulation level), and for rest you just need to send OT read request with corresponding ID and then publish it to mqtt.
I understand ⌠I have now set the average of the required room temperatures for the target temperature. The current temperature is again the average of the measured values of temperatures in the rooms (4 values in total) ⌠I will monitor the behavior of the thermostat
extra (additional) parameters I will try to somehow add âŚ
Thank you
I do a get request, but the result is 0
my flame is always off according to home assistant
Hi @shcherban Have you changed anything in the heating logic in your latest sketch? Below you can see how my boiler is behaving after sketch update (update took place somewhere in the middle of below graphs). Itâs obvious that with new sketch, frequency of boiler temp changes is much higher than previously. Furthermore from whatever reason boiler target temperature is much higher than previously. I should mention, the only piece that was changed is the sketch. All temp settings and outdoor temperature are pretty much the same. Is it normal behaviour or maybe I have done anything wrong?
Wow, thatâs odd
Ill take a look at history maybe some change is by mistake or some piece of test code.
P.S. havenât found any issue. From what i see your minimum temperature changed from 20 to 35 degrees, thats why boiler is turn on more frequently (the lower water temp is the slower it cools down to the threshold when the boiler fires up).
maybe youâve edited your sketch to work on 20? and lost that change after update?
Youâre right. I have also checked previous and current sketches and here is the difference (new on the left)
Honestly speaking I donât recall changing this value at all.
Just recalled yourself writing here on Sept 16, that oplo value is set to 20 by design. So it seems it was set to 20 previously and it was done in very specific reason. Question - What have changed, so that now that value jumped to 35? Shall I take it back to 20 or leave it as is? Eve from the graphs attached above itâs hard for me to asses which option is better. I guess current sketch version (with oplo=35) might be taking much more gass.
I haved added OTA update to my script. Might anyone be interested, I can share it
I still am not capable of seeing my boiler target temperature, while it is in the script. anyone has an idea?
It was 35 from the beginning, 20 was one another (older) sketch and another article. You can safely change it for your needs. 35 is because not all boilers are condensing and 20 just donât donât heat house at all
That would be interesting, hadnât enough time to get hands on ota yet.
Ill post here very basic sketch which will do just basic open therm communication and print to serial to see if thatâs boiler issue or maybe something else.
Yea. I have set it back to 20 degree. My setup is running on Viessmann Vitodens 111W, which is condensing unit. With lower heat level bound set to 35, I couldnât get current temp in my room lower than 23 degree (even if set to 20 or 21)