The fine dust filter and/or the pre-filter is soiled. [HX1]
Remove the dust container.
Empty the dust container over a bin.
Clean the fine dust filter:
Pull the fine dust filter up to remove it.
Hold the fine dust filter over a bin.
Empty the fine dust filter by carefully tapping the rubberised lower edge.
Turn the fine dust filter slightly while you do this to free the dirt from all of the crevices.
Clean the pre-filter:
Remove the pre-filter by pulling it upwards.
Unlock the motor protection filter by turning it anti-clockwise and lift it upwards to remove it.
You do not need to clean the motor protection filter. It can be removed so that the inside of the pre-filter is easier to reach.
Carefully knock the dust out of the pre-filter over a bin.
After cleaning the pre-filter, place the motor protection filter back into the pre-filter securely, making sure it is properly positioned.
Lock the motor protection filter by turning it clockwise as far as it will go.
Replace the pre-filter in the dust container.
To do this, line up the guide lines on the two sections and turn the dust container lid back to its original position.
Close the cover at the bottom of the dust container, making sure it clicks into place.
Once it is clean, refit the fine dust filter in its position in the dust container.
Reattach the dust container to the PowerUnit connector.