Noise from the fan on the Nibe exhaust air heat pump F730 and F750

A noise can occur from the fan on Nibe's exhaust air heat pump models F730 and F750. Usually, when a noise occurs, it may be the bearing on the fan that starts to give. But in this case, Nibe announces that it is the plate that should push the fan up towards the "ceiling" and does not hold the fan well enough. Then the gasket (which should seal the fan outlet) can create a noise. Some think it sounds like a swarm of wasps.

This noise does not have to be constant, but can occur at certain temperatures and pressures. Sometimes it can be difficult to localize the sound, as it can be heard both indoors and outdoors.

But this is a simple error that neither costs much to fix nor is particularly difficult. What needs to be done is to adjust 2 screws that push the fan. Then the gasket seals better and thus the noise disappears.