Also, he told us that we could remove the cover, unplug the air handler, and reverse the black and blue wires to up the speed back to full. I opened the cover and reversed the two wires, but one was called M1 or M2 and the other one was attached to a small fan that looked like an exhaust fan, leading to a rooftop exit. So I put them back to the way they had been. Plus, I didn't hear any increase in air velocity.