Bosch Extractor Hood: "CL" Alert or Saturated Grease Filter Indicator
On Bosch hoods, the "CL" alert or filter icon that appears after a set number of usage hours means the metal grease filters need cleaning to keep suction performance up.
Common symptoms:
- "CL" or the filter icon flashes when the hood is switched on
- Noticeably weaker suction while cooking
- The alert reappears every few weeks of normal use
Probable causes:
This is a scheduled maintenance reminder, not an appliance fault: the internal timer counts cooking hours.
In installations without outdoor ducting, the carbon filter loses effectiveness over time and needs periodic replacement.
Safe Inspection Checklist (Check off when completed):
Switch off the hood, pull each filter's latch, and carefully remove them. Soak them in hot water with degreasing detergent for 15 minutes and scrub with a soft brush, or run them through the dishwasher.
Let the filters air-dry for at least an hour before refitting them, to avoid dripping water or dissolved grease onto the hob below.
With the filters refitted, press and hold the light button or the lowest speed button (check your manual) for 3 seconds until "CL" or the icon turns off.
If the "CL" alert reappears immediately after a proper wash and reset, or the hood sounds different than usual, it's advisable to have a technician check the extraction motor and control board.