How do I reset the electronic filter check indicator lights?

After replacing the filters, plug the unit back in. With the unit powered off, press the lighted "Check Filters" or "Check Pre-Filter" button and hold for approximately 3 seconds until the light turns off. If you change filters before the indicator lights are illuminated, press and hold the appropriate button for 5 seconds with the unit plugged in but powered off; the light will flash red twice to confirm the reset.