york upright oil furnace with direct drive blower motor
Some times blower wheel set screws are not tight when the unit is shipped from the factory. It's one of the first things to check when installing equipment. If it turns out that the blower wheel set screws are tight, check to make sure there is nothing in the blower, such as factory paperwork or styrofoam packing.
"The physician can bury his mistakes, but the architect can only advise his clients to plant vines." -- Frank Lloyd Wright