If the fuse blows again, check the lint chute like JW said, but also remove
the heater and check to see if the element isn't welded to the heater case.
The insulators mysteriously become loose and release the element to expand
and short out against the housing. It is strange but the upper heater chute
will get very hot with very little heat at the element thus bypassing the
limit switch and thermal fuse on the heat side, but the load takes out the
shut it down fuse.