If you are talking about the automatic control dial on the bag door, that isnt about airflow. All that dial does is control how full the bag gets before it shuts off and pops open. The suction/airflow is going to be the same no matter where you set the dial. If it has the blue lines in the dial, the closer you dial to one bar or none the sooner it pops open. The more lines on the dial the longer it runs without popping open. Later luxes have numbers instead of just lines. 1 opening soonest and 4 or 5 going the longest. I set my 1205 about in the middle, but I dont wait for it to pop open anyway. The 1205 is one of my favorites but its not the greatest suction to start with anyway. I hope this answered your question.