Download the Kenmore Air Purifier User Manual Model-BC4027 for free

First of all, the suction control allows you to change vacuum cleaner suction for different fabric and carpet weights.
• Opening control decreases suction for lightweight rugs. 
• Closing control increases suction for upholstery and carpets.
• Keep the airflow passage open. Check each assembly area in REMOVING CLOGS occasionally for clogs.