This will definitely produce noise while the blades are rotating.
Attic fan blades noise.
This might cause due to the striking of the bent blade to other parts of the fan.
If this common noise comes and goes with airflow that s an easy way to tell if this is the problem.
Remove the current worn out bearings and replace them.
The attic fan tends to makes a humming noise when it has a few blades and is running at a high speed setting.
Blades are essential parts of every fan and there is no difference with attic fan as well.
In order to get rid of the hum you need to either operate the fan at a low speed or replace the fan with a new one that has more blades.
While this situation might not be critical to the ongoing functioning of your furnace the obstructing object might be creating unnecessary wear and tear on the unit.
Besides being annoying the vibration could lead to loose.
Due to regular wear and tear these bearings can become worn out or lose their lubrication ability.
Solution 1 to fix this check that each fan blade is angled the same use a level and lay it on top of the fan blades bend the fans blades so that they all are angled the same.
Reason 1 the fan blades are bent upwards and or downwards which causes the fan to be out of balance and therefore wobbles creating a rubbing noise.
Older models of fans are designed to be re lubricated over time and have pre installed places to fill with oil specifically to lubricate the bearings.
Shut off the fan before examining the blades and see if there s a problem or not.
The vibration is most likely the result of a wobble in the fan that could be caused by some loose screws or a fan blade out of balance.
If you ve had your fan for a decent amount of time and are starting to hear noise from the motor area of the unit it may be time to lubricate the bearings.
If the fan blades are imbalanced or bent they can hit against one another or against other parts of the fan.
Attic fans also have small ball bearings that help lubricate the fan s movement.
This sound could mean that something is stuck in the blower s fan blades.
