Buderus Logamatic 2107 KM271 Replacement with WiFi using ESP32 and ESPhome

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122

Hi @bartek666666 , is it still working fine on the Buderus Logamatic R2105 S0, without the issues that @mirekmal had? Thanks in addvanced. I have exactely the same unit and think about this module

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There is not much time to think about, I only have a few left and not planned to order a new batch before beginning of 2026, since I have too many projects currently in pipelineā€¦ But beginning of 2026, Iā€™ll also order a batch of the ethernet extension, so it could be worth it to wait for :stuck_out_tongue:

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Thanks, great to here it that you still support it! For now I know that is geat job what Youā€™v done so thx :slight_smile: Im planning to install heat pump in hybrid with buderus next year so I think I will wait for next year but first I have to read more about features of this solution beacause Im on the beginig.

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Thank you, Daniel, this thing is just wonderful and I am now able to adjust the behavior of my furnace with home assistant in the morning and in the afternoon based on forecasted temperatures, which is great.
I do have one question that I meant to ask as we just changed to winter time this week end ā€¦ I am still adjusting the time manually, but perhaps there is a way to do this using this module???

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More generally, I am interested to find out what other automations people have developed in order to optimize the operation of their furnace using this module with home assistant

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Hi Lepelot,

it is possible to set the date/time through the KM271, but it is not integrated into my ESPhome component. You need to use lambda functions and generate the adequate packages to send to the controller.
In dewennis firmware, at least the documentation states, that it can adjust date and time:

For ESPhome, you should be able to find the right commands to do this in dewennis code and use a lambda to write it to the Buderus controller. An example for a ā€œwriting lambdaā€ triggered by button press can be found here: ESPhome-KM271-WiFi/buderus-km271_en.yaml at d5cb4ca5ac068f161077ae40ddea4f01b430b968 Ā· the78mole/ESPhome-KM271-WiFi Ā· GitHub

Have fun :slight_smile:

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Great, thank you Daniel, now that I know that it is possible, I do some digging starting with the links you have provided. Thanks for your help.

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Do you still have any KM271 Wi-Fi modules? Iā€™ve added myself to the watchlist in that shop. Iā€™d be interested in one. I have an R2107M-S0 S09 at my parentsā€™ house. Iā€™d like to do some work on it to better understand how the heating system works :slight_smile:

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Hi niltrip,

Iā€™m currently completely out of stock. Currently Iā€™m very occupied with other stuff and I expect to order a new batch around end of the year (together with some ethernet extension). Iā€™m also waiting for some feedback about the Ethernet extension prototypes.

Regards,
Daniel

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Hi Daniel, thanks for the reply. Iā€™ll wait then; Iā€™m on the list. Thanks for this great project.

Best regards,
Christian

132

Hello! Thanks for this wonderful device. I have added myself to the waiting list too.

I have been reading a lot about energy efficiency and I would like to yield some savings. Do you know if it could be possible with the help of this device and providing that one uses smart TRVs, to optimize the flow temperature (Vorlauftemperatur) as well as heating curve (Heizkurve)?

Maybe it is a bit of a moonshot. :slight_smile:

Cheers!

133

Hi,
The project seems to be really great and based on the comments working fine.
Also added myself into the waitlist in tindie and looking forward to order one.
Thanks!

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I moved. I donā€™t have a Buderus heater anymore. So I have one of these laying around. Anybody interested?

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Yes, I am. It looks like it took longer with a new charge. How old is your card?

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I am also interested, living in Austria, I guess post would be fine, just let me know.
Thanks

137

Hello Daniel, Hello the Community!
I have been using the KM271 module with ESPHome and Home Assistant for a couple of year and although my ESPHome yaml could certainly be improved/simplified, It is doing a great job for me. The reason for my post has to do with my WIFI connection. Up to a couple of days ago, I was using an old Cisco Access point and I decided to replace it with a simple WIFI repeater (ME1500X | RĆ©pĆ©teur WiFi 6 AX1500 - MERCUSYS). Everything seems to work OK except that now the device tracker (device_tracker.km271_for_friends_5dfbc0) now shows up in Home Assistant as ā€œnot_homeā€ although it is connected and all other values and controls are OK. This is not very critical as I can use another value to show that the module is powered, but it is a bit annoying because I donā€™t understand why it is doing this. It does go back to normal if I use the main WIFI SSID but I canā€™t leave it like this as it is very weak in my boiler room. Thanks for any suggestion/idea you might have.

Update : reponse from Chat GPT ā†’ Home Assistantā€™s device_tracker for ESPHome often relies on network presence detection (router or integration). When the ESP32 connects to the Freebox main SSID, HA can see the device through the Freebox integration, so it marks it: home

But when the ESP connects to another SSID the **Freebox router no longer reports that device, so Home Assistant thinks: not_home