There are a lot of different Hampton Bay Model AC 552 units with completely different configurations. Ours is a four light unit. The unit stopped working after about 20 years of use (not bad!). So, we needed to take it down.
First: Make sure all power is off to the unit/room.
Removing the glass light fixtures was easy. Just press in two metal fingers that hold each of them in place.
Removing the light fixture was also easy with three phillips screws to be removed and the plastic electrical assembly wire unit unhooked (via a push in tab).
Then the blades were taken down by turning each blade to a cut out section of the metal plate below them (held on with a nut that cannot be easily removed and is not supposed to be removed) and taking out the two phillips screws that hold each of the five fan blades in place.
That left the main unit with no clear way to get it down. The screws at the very top were hidden. You access them by turning the unit counter-clockwise. This may be hard to do if the unit has been in place for a long time. We took a butter knife and ran it around the top of the unit between the unit and the ceiling, and that loosened it enough to turn it the inch or so to reveal the screws.
Remove the screws and lower the unit to allow taking off the plastic caps and unhooking the wires. Again: Make sure all power is off to the unit/room and even then treat the wires as though they were live by only touching the wire casing.
The only tricky part is revealing the hidden screws at the top of the unit (which is why I am posting this). My brother knew about them. We were at a standstill in removing it without his help.