Your Philips Air Purifier or Humidifier needs to be reset after replacing a filter.
1- On the side of your purifier/humidifier, you will see the air quality sensor lid.
2- Below this air quality sensor lid, you will find the air quality sensor inlet.
3- The reset button is a red button located under the air quality sensor inlet.
4- Make sure your appliance is connected to the power supply.
5- Use a thin object to press the reset button to reset it.