Zehnder ComfoAir Q350 + LAN-C – HA integration connects but unusable (no sensors / no control)

Configuration
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Zehnder ComfoAir Q350 + LAN-C – Home Assistant integration connects but is unusable (no sensors / no control, always errors). What is the recommended integration approach now?

I’m using a Zehnder ComfoAir Q350 with ComfoConnect LAN-C.

Current behaviour with Home Assistant (core ComfoConnect integration):

  • Integration connects to the device
  • But no sensors are returned and no control works
  • Always results in “unexpected error” / timeout behaviour when trying to interact

Other observations:

  • Zehnder ComfoControl app works locally without issue
  • Google Home can see the device but reports it as offline
  • Network is stable, same subnet, static IP
  • Removed custom_components override and tested clean HA setup

It feels like LAN-C accepts the connection but does not respond properly to commands or complete registration.

Before I go further (e.g. wiring relays or moving to Modbus):

  1. What is the currently recommended way to integrate ComfoAir Q / ComfoCoolQ with Home Assistant?

    • Is the LAN-C integration still viable?
    • Or generally considered unreliable / legacy?

  2. Are people successfully using LAN-C with HA in a stable way?

  3. For those wanting:

    • Away / Boost control
    • Supply / extract / outdoor / exhaust temperatures
    • Humidity

    what setup are you actually using in practice?

  4. If starting again today, would you:

    • Stick with LAN-C
    • Use MQTT bridge
    • Move to Modbus (ComfoConnect Pro)
    • Or something else?

Thanks

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Since this is an integration in core, you may want to collect some log examples and screen shots of your findings and do an issue to report it.
¯\(ツ)/¯ Sounds like you are looking for…