DIAGNOSIS The filter reset procedure was not completed after installing new filters.
FIX With the unit on, press and hold the 'Filter Reset' button for 3 seconds. The indicator light will blink and then turn off. The timer is now reset to zero.
IF THAT DIDN'T WORK Ensure you are using genuine Coway Airmega AP-1512HH filters. Some third-party filters lack the required RFID tag and will not allow a reset.
HEADS UP The filter light is on a 12-month timer by default. You must manually reset it even with genuine filters.