Hello! I was able to find, on page 12 of the User Manual, that this is the Filter Remind feature letting you know the Grease Filter needs to be cleaned. You can also turn this feature off using the steps listed on pages 12-13. Beginning on page 31, there are detailed instructions on how to clean the grease filter. If you don't already have the manual, feel free to use this link (https://bit.ly/2OlBfQJ) to download it. ^Jecca