Arrived at location on 11/10/22 - Powered unit on. Could hear the blower humming. Powered unit off and removed top panel. Removed cover over blower. Inspected bearings on blower. No slop and didn’t hear any grinding. Bearings seemed good. Lubed shaft that blower sits on and spun blower. Noise is gone. Put panels back together and powered unit on. Unit is heating without any noise. If problem returns bearings will need to be replaced. Okay.