Writing unregistered parameter ID_Einst_BA_Lueftung_akt (ventilation mode, KHZ-LW80) causes socket to hang/become unreachable

[Oxbow6]

Description

Writing the ventilation operating mode parameter ID_Einst_BA_Lueftung_akt via the
luxtronik2.write service (Home Assistant, BenPru/luxtronik integration on top of
this library) reliably causes the heat pump controller's TCP socket to hang and
become unreachable shortly after the write completes.

Environment

• Heat pump: Alpha Innotec KHZ-LW80 (compact unit: heat pump + ventilation module,
  ventilation controlled via a "Compactmodul" plugged onto the main Luxtronik board)
• Controller firmware: V1.90.0
• Integration: BenPru/luxtronik (Home Assistant, domain luxtronik2)
• Underlying library: python-luxtronik 0.3.14

Steps to reproduce

1. Call the write service with an unregistered parameter:

   service: luxtronik2.write
   data:
     parameter: "ID_Einst_BA_Lueftung_akt"
     value: "Automatic"

2. First write appears to succeed (no immediate error).
3. A second write shortly after (e.g. value "Party") times out.
4. Shortly after, the coordinator's polling starts failing entirely:

   Socket error during read/write
     File "lux_helper.py", line 316, in _write
       cmd = struct.unpack(">i", self._socket.recv(4))[0]
     TimeoutError: timed out
   
   Failed to connect: [Errno 113] Host is unreachable
   Error fetching luxtronik2 data: Error fetching data: [Errno 113] Host is unreachable
   

5. The controller recovers on its own after a few minutes (no data loss / heating
   itself is unaffected — the heat pump continues operating autonomously).

Notes / suspected cause

• ID_Einst_BA_Lueftung_akt is not in luxtronik/definitions/parameters.py, so it's
  written as a raw/unmapped value rather than through the normal enum-mapped
  parameter path (compare with the working ID_Ba_Hz_akt → "Automatic"/"Party"/...
  mapping).
• The manufacturer's own built-in web interface (same device, same port 8889) can
  set this exact value reliably and without any connection issue — so the controller
  itself accepts the parameter fine when encoded correctly. This suggests the issue
  is on the encoding side of this library/the raw-parameter write path, not a
  hardware/firmware limitation.

Request

Could ID_Einst_BA_Lueftung_akt (ventilation operating mode: Automatic/Party/
Holidays/Off) be added as an officially mapped parameter, similar to
ID_Ba_Hz_akt? This would make ventilation control on KHZ-LW80-style compact units
usable without risking the socket hang described above.

Happy to provide more logs / test a patch if useful.

[Guzz-T]

Controller firmware V1.90.0 is already pretty outdated. Please consider using the latest firmware (V3.92.3).

ID_Einst_BA_Lueftung_akt is available in python-luxtronik > v0.3.14.
Could you try setting the parameter using only this library? Check the docs for more information.