Samsung ERV - When Excessive Noise Is Heard

Samsung Electronics 9-15
9-4-15 When excessive noise is heard
Clean Filters.
No
Yes
Yes
Yes
Yes
Are Filter well cleaned?
Yes
Yes
Is the unit making excessive noise?
Install Heat Exchange Element and
filter properly.
Is there any substance inside the Duct?
Are Heat Exchange Element well cleaned?
No
Eliminate Dust or other substance.
No
Eliminate the substance.
No
Measure RPM and fix it.
No
Is Fan Motor working properly?
Replace or repair PCB.
Are Heat Exchange Element
and Filter installed properly?