You can remove a device from the web UI of this Thinka. Click the "Device -" icon which means removing device that is at the top of the page, and follow the instructions. The manual that is available for this device will have instructions on how to exclude this device. Most of the time you will have to triple click the "B" button. Here is the images for help to show removing a device
Click "-" to start removing device
Click "Start" button
Set your device in to learn(exclusion) mode and wait it to be excluded.
Removing Z-Wave device has been completed