My Roof air Story
Before we Purchased the "Bus", it had been damaged in a hail storm and the roof had been replaced with a one piece metal roof. The new roof was fastened only at the edges and is held down in the middle by the vents and air conditioners.
On hot days the metal roof would expand causing a pillowing effect with e AC and vents acting like the buttons on a pillow.
With the AC's running the condensate would fill up the areas around the air conditioners and rise above the gaskets and lower pan of the AC unit. At this point it would suddenly rain like hell inside.
I looked at a number of options to cure this problem and settled on the following.
I removed the AC units from their positions.
I purchased some vinyl planking and cut it at 45 degree angles and fastened them around the AC opening with lots of sealant. I then re installed the AC units over top of the vinyl planks in affect raising them 3/4 of an inch. I also widened the openings to the ceiling air ducts considerably while I had the access.
With new gaskets installed so far no more interior rain falls.
The fix of course meant that the interior baffles of the AC units no longer would make contact with the AC units.
I also found on the rear unit that it had never made contact as it was a lot more than a 3/4 inch gap between the baffle and the bottom of the AC unit. This would explain the poor operation of the unit through the ceiling vents when the shutters on the bottom of the unit were closed.
Using pipe insulation and metal tape I was able to seal all of the gaps on both the front and rear units.
The difference on the first run was amazing. There has never been so much airflow through the ceiling vents ever. It blew dust, Styrofoam chips and all of the sundry items that had been lingering in the ceiling vents for years all through the RV. ( I guess it needed vacuuming anyway).
I can now run either AC and have air blowing out all of the vents, It still takes both units to cool the Bus on a hot day but I can run with the shutters closed on the bottom of the AC units and not have the vertical torrent of air
under each unit.
But best of all, its not raining inside.
I found the best way to look for gaps between the interior baffles and the bottom of the AC unit was look up from one side while shining a bright flashlight form the other. I was amazed at the number of gaps.
Sealing them all really boosted the performance.
I hope this info helps anyone with similar issues.
Sorry no pictures as I find it dificult to hold a cammera and flshlight and tools all at the same time.
Dave and Jean
34 ft 1996 RAVEN
Brampton On. Canada