Roof air conditioners are divided into 3 parts
There is the part you see on the ceiling, this is different for ducted and non-ducted units
There is the part on the roof, Same for all takers.
There is the part in between and that too is different for ducted and non-ducted.
NOW: if you have ducted.. Tell us.. What make/model do you have? There may be a lower cost option though CW is not the best source here.
For example: I have a Carrier Air V in the front, and 1/2 of a Carrier in the rear (The bottom 2 pieces) the top part is an Advent Air, with an ADAPT-A-KIT CONNECTING THEM.. sOUNDS A Whole lot harder than it is.. I will describe the procedure.
Remove inner cover, Unplug upper unit from lower unit, Remove 4 bolts, Remove upper unit,
Position new upper unit (Replace gasket if necessary) re-install 4 new bolts (included in kit) Open control box and remove one of the MOLEX connecters (Easy for me, there is a trick, which I know, to it however) and install new connecter in the kit.
Plug in "Y" cable (there is only one way to plug it in ) and plug upper unit into the remaining connector on the "Y".. Re-install inner cover, power on.
That easy. You do not disturb the ceiling unit at all (Save the control box is part of it) it remains in place throughout.
The reason they need to be custom ordered for ducted is to make sure the ducts line up. Non Ducted do not have that issue.
But it may be possible to just replace the problem part and leave the ceiling parts alone.
