Your Philips Air Purifier or Humidifier needs to be reset after each filter replacement. This is done to activate the counting system for the new filter(s).

Also, your air purifier/humidifier is equipped with a filter replacement alert. It warns you when the filter needs to be cleaned (pre-filter only) and replaced.

If you do not reset the air purifier or humidifier after replacing a new filter, the appliance will alert you to replace a filter.