Post count: 367

    Most if not all KNX devices have some blocking-input, which prevent functions (like switching on) if certain circumstances are met.
    You just need get get the temperature from one device and have some <= logik (on a device with logic or some logic server like the Gira homeserver) to send 0 or 1 to the blocking group address of your fan controller. This way you can prevent turning on the fan when temperature is low.