[LuxtronikHeatpump] Finding the currently drawn power

I’d like to update the LuxtronikHeatpump binding to include the power currently being drawn. In the luxtronik UI (, it appears as “actual capacity” (eg. 5.01 kW).

I’ve not found much documentation online. Java Webinterface - loxwiki - loxwiki is the best I’ve found so far. It closely resembles the LuxtronikHeatpump binding implementation, but the binding has a few extra values.

I think I’ve tracked down the approach value from the binary stream, value number 257. I though I’d quickly ask here if someone can confirm this before I open an improvement request and submit a pull request.

BTW, “powerActualValue” the value number 188 always returns 0 from my device. Further, the units is kWh, instead of the (k)W that I’m currently looking for.

@sgiehl perhaps you know?

Hi @jamie_townsend
I assume you have a newer heatpump with a software version > 3?
Some newer heatpumps are serving more channels. Mine actually only holds 232 channels. Newer heatpumps are serving 260.
I’ve actually gone through some channels with another forum user and we were able to identify some of them based on the UI and the socket response. Maybe you are able to confirm them and maybe identify some more?

I’ve prepared some changes on my fork. See Comparing openhab:main...sgiehl:luxtronikchannels · openhab/openhab-addons · GitHub

Hi @sgiehl

Yes, my software version is V3.85.5 (r6309).

I downloaded your luxtronikchannels branch and can confirm that channel 257 (PowerActualValue2) contains the values I’m expecting.

After only a few hours in use, I can’t confirm much, but here’s what I have:

Background data:

  • outside temp overnight +/- 10 (heat pump is outside)
  • minimum hot water temp 40
  • maximum hot water temp 50

Channel 232 - data values +/- 100 when warm water is not being generated, +/-10 when warm water is being generated, spikes to -115 when generation starts (:flushed:)

Channel 233 - data values +/- 97 when warm water is not being generated, just to 320 when generation starts, slowly increases to 480 when generation is finished and then drops back to +/- 97 - probably a return temperature in the heat pump

Channel frequencyCompressorTarget (236) - data value always 0, jumps to 3000 when warm water generating starts, spiking 10 minutes later to 3250, immediately drop to 2950, then continually increasing to 3250 by the end of the generation, immediately dropping back to 0 when generation finished

Channel 237 - data value always 0 when warm water is not being generated, spikes to exactly 50 when heating starts, then drops immediately to exactly 30 until heating finishes

Channel 238 - data value always 0 when warm water is not being generated, jumps to exactly 100 when heating starts, spikes to exactly 115 when heating finished, then drops immediately back to 0

Channel 244 - data value always exactly 600

Channel 249 - data value generally sinking from 260 to 180 when not heating, goes up steeply when heating starts, then still up but slower until heating finishes, topping out at 440, after heating stop drops steeply to around 260, then generally sinking - probably a temperatur

Channel 250 - similar to 249

Channel 251 - data values are generally rising from -150 to -90 when not heating, spikes to 75 when heating starts then +/-35 until heating finishes, spikes to -240 then increases fairly quick to -150, then generally rising again - interesting data pattern, but I can’t figure out what this one could be

Channel 252 - data values exactly 900 when warm water is not being generated, jumps (almost) immediately to exactly 1150, while generating, dropping immediately and exactly back to 900 afterwards

Channel 256 - data values always exactly 5

Channels with no data (always 0) - 234, 235, 239, 240, 241, 242, 243, 245, 246, 247, 248, 253, 255, 258, 259

If I can help further, please let me know :slightly_smiling_face:

Thanks for the details.
Are you able to map any of those values to those shown in the Webinterface?

I’ll have to try when the heat pump is running. Since we also have vacuum pipe thermal collectors, the heat pump doesn’t kick in much at this time of the year, and then, only in the wee small hours, when I’m usually asleep. I’ll keep an eye on it and let you know if I can map anything.

Solution for this question: Use GitHub - sgiehl/openhab-addons at luxtronikchannels

Thanks @sgiehl !!

Ok. Let me know if you find anything. I’ll wait a bit and create a PR for at least those channels we were able to identify.

Hmm… powerActualValue2 (channel 257) is not what we thought it was

Channels 233 & 249 have the right kind of shape, but aren’t it either. Schade! No closer to the device reporting it’s own power usage :frowning:

Hey @jamie_townsend
Didn’t have any time to look into this the last week. Did I get that right, that you assume it’s not the correct channel based on plausability of the evolution chart of the captured data in openhab? Or did you check if the heatpump itself reported another value then?
Another user also reported to me that 257 would be the actual power value, but not sure if he validated it in that way…

Hi @Sgiehl
Right, this value can’t be the power being drawn as this value only increases by 200-400 and during the same time the power drawn from the grid increases by 1000-1400. The value seems to have the right kind of shape (gently increasing), but if it was being reported at 20% of it’s actual value (and I’ve seen much stranger offsets when communicating with devices at a binary level), the “real” value when not generating heat would be higher than the total power drawn from the grid.
That said, I can confirm that the channel 257 contains the value shown in the UI with the label “actual capacity” under “system status”.
HTH, Jamie

i can confirm 257 is de actual value in W
but this is not the electrical power, its the heating power.

so, the power the heatpump is generating and putting into the heating system.
this value you can use together with the electrical power to calculate the COP

heating power / electrical power = COP

Nice. Thanks for that. Any idea if it’s possible to get the electrical power out of the heatpump itself? I haven’t found a way.

I dont think so, ive installed a kwh puls meter between the circuit breaker and the heatpump to messure the elektrical current.

I dont see an electrical wattage in the online gui of the luxtronix

Although the current electrical power is not available, one could estimate it.

  • electrical power = heating power / COP

For the COP, some values are known (6 data points for this one: p23 of https://mw.ait-group.net/files/docs/DE/A0010/83059000.pdf). Hence, we could estimate COP (as a function of external and flow temperature) and eventually estimate the electrical power.