The AQM sensor is not reading properly on my Guardian air purifier (AC9400, CDAP4500, CDAP5500)

The sensor on the unit may need to be cleaned.  Please try the following:

• Power off the unit and unplug
• Open the small door on the right-hand side of the unit (rectangle on CDAP4500/CDAP5500,pictured below)
• For AC9400 the sensors are located on the back of the unit. (Pictured below)
• Blow out that area with canned air, or clean with the vacuum hose
• Shut the flap, plug back in and power on

This cleaning should allow for the unit to re-calibrate and the proper reading for the particulate matter should display.

*Please note when the air does have higher amount of particulate matter, the sensor will recognize that, the numbers will rise and the colors on the display circle will change.

*CDAP4500/CDAP5500

*AC9400