OP here. I resolved my Brisk Air issue. When Won Hung Lo installed the squirrel cage fan on the motor shaft, he put it on too far and it was rubbing against the styrofoam housing. I went on the roof snfd removed the upper styrofoam housing and spun the fan with a leaf blower. I have done this previously to loosen up tight bearings, Loosened it up and moved it back 1/8" and all is well.
This preserves my 25 year record of never having to have warranty work done at a dealer. Of course 40+ years as a General Contractor and being a former ASE mechanic helps.