KNX Climate – Fan speed (DPT 5.010) without “Auto” step + separate Auto/Manual fan mode (DPT 20.120)

[elmondogri]

Problem

Hi! 👋
I'm integrating an Airzone Aidoo KNX v2 (AZAI6KNX2HI2 for Hitachi units) with Home Assistant via the KNX integration.

Everything works fine — on/off, HVAC mode, temperatures, etc. — except for the fan control.

The Aidoo exposes two independent KNX objects:

Function	DPT	Values
Fan speed	5.010	1 = Low, 2 = Medium, 3 = High
Fan mode	20.120	0 = Auto, 1 = Manual

When the Aidoo is in Auto mode (DPT 20.120 = 0), it automatically manages the fan speed.
When it's in Manual mode (DPT 20.120 = 1), the installer can control 3 discrete speed levels (1-3) via DPT 5.010.

In Home Assistant, the KNX climate entity currently assumes that fan_speed_mode: "step" uses 0 = Auto, which doesn’t exist in this device — and there’s no way to handle the Auto/Manual object (20.120) separately.

Expected behavior

It would be great if the KNX climate integration could:

• Support an additional parameter (e.g. fan_mode_address) to map DPT 20.120,
• Or provide a way to disable the implicit “0 = Auto” behavior when using DPT 5.010 fan speed steps.

Question

What’s the recommended way to handle the Auto/Manual fan mode (DPT 20.120) alongside fan_speed_mode: "step"?
Would you consider adding a dedicated configuration key (e.g. fan_mode_address) for this use case?

Thanks a lot for your work on the KNX integration 🙏

My configuration

knx:
  climate:
    - name: "Clim Studio"
      temperature_address: "0/0/57"
      target_temperature_address: "0/0/55"
      target_temperature_state_address: "0/0/56"
      on_off_address: "0/0/53"
      on_off_state_address: "0/0/54"
      controller_mode_address: "0/0/32"
      controller_mode_state_address: "0/0/44"
      fan_speed_address: "0/0/48"           # DPT 5.010 (1–3)
      fan_speed_state_address: "0/0/49"
      fan_speed_mode: "step"
      min_temp: 16
      max_temp: 30
      temperature_step: 0.5

[farmio]

Hi 👋!

Unfortunately these things are either not exactly specified in the KNX standard or manufacturers don't adhere to it. For a protocol integration like KNX is, it's nearly impossible to cover all edge cases and manufacturer specific / proprietary features in a generic way.

Like here, it seems DPT 20.120 is a random choice as it doesn't really coerce to knx standards.

... or it's confused with DPT 20.102 - then you may just try to set it up as `operation_mode_address` and use "Auto" and "Comfort" presets.

---

> Support an additional parameter (e.g. fan_mode_address) to map DPT 20.120, > Or provide a way to disable the implicit “0 = Auto” behavior when using DPT 5.010 fan speed steps.

As a workaround I'd suggest to do the opposite. In some logic (automation or whatever) you can use the 0 value as trigger to send to the "auto-GA" and vice versa.

Other than that, have a look if the device can be configured to use a different way to set "auto fan mode".

[elmondogri]

thank you i will check