Sealing strip defective
With regard to the horizontal sealing strip, we would like to ask you to check in advance whether the following instructions have been observed during installation.
In our installation instructions, we point out that the long sealing lip is pulled off at the tear-off edge when installing the sill. If this has not been done properly during installation, the lip will rub on the sill and become jammed during opening, which will eventually cause the sealing strip to detach.