The installation instructions say:
"The Top Rail and Sliding Panels at each side are offset to provide the
proper pitch to the rear of (5/16"). This is necessary for proper condensed
water utilization and drainage. If you are not using the side panels for
any reason, this pitch must be maintained!"
When I set the unit in the window as instructed it tilts slighty forward.
In other words, the outside end is slightly higher than the inside end.
This makes sense to me, because if it tilted the other way it would be more
likely to slide out of the window. But it bother me that the instructions
say "proper pitch to the rear". And any rain on the top of the unit will
run towards the window.
This is Fridigaire 205391, a 6,000 BTU unit, bought at Lowes. Lousy
pictures in the installation manual.