The ventilation system
This is the broken oder even melted rubber insert, which is supporting the bearings of the fan axle. Manufacturer replied fast, no worry, see below!
The device is now out of use.
Listen to the severe noise of the fan:
See also how bad the tolerance is; in this video the fan is dismounted and I highlight the problem by pushing the motor by hand:
The fan is made by a contractor to Enervent. I contacted this company and they replied fast and friendly: this failure of the fan IS NOT NORMAL. I should get a new part on behalf of the manufacturer.
The ventilation system is designed and built for the Enervent Greenair-unit. This extraordinary machine has a heat pump as an additional feature. The unit has been now around five years in use and has proven to be quiet in use. The quality of the machine seems to be suffering from various not-that-good components, such as the heat pump-unit, which has been replaced twice. The factory showed good responsibility in solving the issues with the heat pump-unit. Apparently, they had used some lower-quality components or parts for the heat pump and since those updates or repairs, the unit has been running well.
Here the ventilation unit Enervent Greenair ready for use.