How do I reset the filter change indicator light after replacing the HEPA filter or pre-filter?

After replacing the appropriate filters and plugging the unit back in, with the unit powered OFF, press the lighted button and hold for approximately 3 seconds until the light turns off. If you replace filters before the indicator light illuminates, press and hold the appropriate 'Filters' or 'Pre-Filter' button for 5 seconds while the unit is plugged in and powered off — the light will flash red twice to confirm the reset. (Page 6)