Ran into this gem yesterday

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Original call was for blower motor rattles,and has poor airflow. House is for sale and homeowner wanted us to replace the motor to improve air flow. There is a total of 3 supplies, 2 - 6's and the pièce de résistance a 5" split with a tee right off the plenum and then split yet again by another tee to 2 more 5's.

And yes indeed that is an aluminum dryer vent 90 off of the draft diverter going into type b vent that is ran backwards all the way to the chimney.

The blower motor was completely caked with dirt as well as the coil. I informed him that the last thing he needed was a new blower motor.