Water Intrusion

[blindhanger]

We found wet throw rugs in our new Sundance 273RL after the last 2 rains. No evidence of water on walls or ceiling. Both rugs were directly under ducted A/C ducts, both on the same side of the trailer, both on the same end of the A/C. Probably lucky there were rugs or we might not have pin-pointed the location.
Is the A/C supposed to be sealed from rain?
Are the ducts somehow exposed to the elements?
Any and all help is appreciated.

[roady]

The AC unit should be sealed from water at the roof, but a leak path could exist that might only show up under certain circumstances.
The AC will create water through condensation as part of its operation. The condensate is supposed to drain away from the unit and usually onto the roof. However if there is a leak path around the unit, or an internal leak or blockage of the drain the condensate could find its way inside the coach.

[EnduroRdr]

Roady is correct, a plugged drain outlet can cause a backup of condensation and possibly drip into your coach. In very high humidity conditions your a/c will be pulling a lot of moisture out of the air in the form on condensation. If your drain (usually just a slot or tube that allows the evaporator pan to drain to outside roof) if there is dirt or funk blocking this tube then your pan can overflow and quite possibly run down through the inside ceiling opening.
But since you said this event was after a rain I’d suspect that your roof seal under a/c unit has a gap in it and wind may have blown the water back under your a/c unit and found a path inside.
Go to YouTube and look up rv a/c installation.
You will see there is a gasket (more like a thick rubber band) that is installed around the 14” standard roof vent opening on top of roof but under the a/c. Your a/c should sit on the rubber gasket seal and be clamped down by the 4 long bolts coming through inside the opening at the corners.
Since your roof opening does not have a raised area there - the rubber seal is the only thing keeping water out. Especially in windy conditions where water is blown under the a/c. It is especially important on rooftops that are flat and don’t have an arc or pitch to drain water toward the sides.
If the gasket develops a gap then it is easy for rain or a/c condensation to leak into your rv.
Most rv stores sell replacement gasket seals if needed.

[blindhanger]

Thanks EnduroRdr. I removed the A/C interior cover and the baffle that directs air to the duct system. No obvious signs of leaks. I checked the torque of the 4 mounting bolts (with hand tools - no power drill) and found all bolts to be what I consider less than snug and 1 bolt less tight than the others. I tightened them in a crossing pattern. After a significant blowing rain there were no leaks.