When the damper control panel is in the lowest position, the air duct is fully open (that is, the air volume is maximum); when in the highest position, the air duct is closed (that is, the air volume is the smallest).
When the door control panel is in the lowest position, the air channel is fully open (i.e. the maximum air volume) and at the highest position, the air channel is closed (i.e. the air volume is minimal).
When the damper control panel is at the lowest position, the air duct is fully open (i.e., the maximum air volume); when it is at the highest position, the air duct is closed (i.e., the minimum air volume).