Furnace was making a rattling noise upon arrival. After further assessment I found that there were a couple loose metal pieces on the duct work. I tightened these pieces down and then found that the condensate drain was loose and vibrating against the furnace, on top of that the control board metal panel was loose and vibrating as well. I tightened all of these pieces down and then found that the noises went away. I tested the furnace on low speed and high speed and did not notice this sound anymore.