What does the 'CL' flashing on the display mean, and how do I reset it?

The 'CL' flashing on the display is a reminder to clean the air filter, which appears after 240 hours of use. After 15 seconds, the display will revert to its previous state. To reset the reminder, press the LED button on the remote control 4 times or press the MANUAL CONTROL button 3 times. If you do not reset the reminder, the 'CL' indicator will flash again when you restart the unit. (Page 37)