Miele DA 249-3 Operating And Installation Instructions page 20

Replace the active charcoal filter when
the
Replace the filter at least every 6
months or when it no longer absorb
odors efficiently.
^ After replacing the charcoal filters,
press and hold the charcoal filter
button for about 3 seconds to reset
the charcoal filter timer.
The indicator light will go out.
^ If the charcoal filters are replaced
before the timer has reached its
maximum, the charcoal filter button
should be pressed for 6 seconds to
reset the counter to zero.
20
lights.