The nice thing about this site - most of you can identify with my frustrations:
This furnace was inspected once each year for the past five years, but for some reason no one pulled the EAC pre-filters (screens) - both were blocked solid, and saturated with humidifier runoff. Nothing like trying to suck air through a wet blanket!
What really frosted the cake was the 1" thick slab of sound lining that pulled off the blower cabinet, and the technician attempted to tape it back in place with strips of 3/4" electrical tape! Well, the tape let go, and now the sound lining was sucked up against the blower housing. Yep, any air making it past the "wet blanket" was just cut in half again.
P.S. It only took me 5 hours to rebuild this 22year old sucker!