Question about Venta LW45 Original

I have been using the LW45 for a few years and mostly during the heating season.
This year the unit greeted me with a grinding noise. The ball bearing must be defective.
My next port of call: https://www.venta-air.com/de_ch...

No, we have been using this model for years. On level 1, the noise level is very pleasant. On level 2, it is only usable at night. But nothing of grinding noise.