Coway AP-2021A Gray User Manual page 22

RESETTING SENSOR
Setting dust sensor sensitivity
Press and hold the clean mode button and the information button
simultaneously for more than 3 seconds while the purifier is running.
With a buzzer, PM2.5 lights up and then flickers at an interval of 1 second,
and the current sensitivity setting is displayed. Pressing the information
button again will change the sensitivity in 7 levels (001: Sensitive +2,
002: Sensitive +1, 003: Sensitive, 004: Normal, 005: Insensitive, 006:
Insensitive +1, 007: Insensitive +2), and press the clean mode button and
the information button at the same time for 3 seconds to exit.
Resetting gas sensor
Press light and information buttons at the same time within 30 seconds
after power is applied, and hold them for 3 seconds.
A buzzer sound will be heard and it is reset to the factory setting.
21
3 sec. 3 sec.
3 sec. 3 sec.