Where my I obtain this drawing?
There were several issues with the 2016 Dometics. I had them all, and experienced the condensation that you are having.
At some point I posted a whole series of posts with pics here...but the gist of it is;
There is a drawing from dometic that indicates the locations and sizes of additional holes to drill to allow excess water to flow to the outside of the ac. Part of what is happening is that the drip pan is overflowing into the ducts.
Secondly, I found that there were mounting holes that were left unplugged, and that these drained directly into the ductwork. Use a small light in the plenum shining up on the drip tray and if yours are not plugged you will see light coming through. I think it was toward the front just inside the roof gasket
Third, excess rainwater enters the ac unit through the cover where the top fits into the bottom. Mine had big gaps and the water would overwhelm the drip pan and go right into the ductwork. My fix was clear Gorilla tape around the entire seam.
Fourth, my duct run was open on both the front and the rear, and the ducts were not sealed at the plenum...you guessed it...cold and warm air mixing produces condensation. Block off the ends inside the ducts if they are open to the caps.
Take care of these and you should be good. Once I did this I never had another drop of water, and never had any more ceiling condensation.
But...my ac units both leaked under the gaskets. I took it back to the factory for that
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What a horror show it was, because these ac units were new and nobody knew what was going on.
On edit...I also used some stick on silver insulation inside the ductwork to line the ceiling as much as I could. I would do this only as a last resort...I think the other fixes will cure the issue. This insulation was one of my first attempts at figuring out what was going on. Might not be necessary...
Hope this helps you.
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