You can make a room type unavailable for bookings by following these steps:
- Go to Settings -> Restrictions -> Restrictions for check-in check-out and /or stays and click “Restrict period”.
- Enter a name for the restriction and indicate the date range when this setting should apply.
- Choose the room type you want to block from the drop-down.
- Check “Stays not allowed (including check-in)”.
The above is also explained in this video: