Miele PDR 908 HP Operating And Installation Instructions page 62

Cleaning and care
Deformation
Deformations indicate that the filter has
become blocked and worn by continu-
ous use.
Cracks, tears, indentations
Fluff will blow into the heat exchanger
through cracks and tears and will cause
obstruction.
Indentations indicate that the filter has
become blocked and worn by continu-
ous use.
62
White residues or residues of other col-
ours
Residues arise from laundry fibres and
traces of detergent components which
can clog the filter. They can be found on
the front and side edges of the filter. In
extreme cases, they can form stubborn
crust.
Residues are a sign that the filter is no
longer a snug fit at the sides, even if it
appears to be perfect: fluff is getting in
unfiltered at the edges.
If these residues appear on the filters
again soon after cleaning, the filter must
be replaced.