Why do I find dark dust when cleaning the furniture?

When cleaning the furniture, dark dust is often noticed and one may wonder what causes this.

It could be that the vacuum cleaner or ash vacuum dustbin has leaks, so it would be advisable to check the filters and the airtightness of the components.

On the other hand, pellet stoves operate under negative pressure and, therefore, should not have ash leaks during their use.

In case of problems with the smoke fan, the stove would immediately shut down and the remote control would display a safety signal.