montana Big Sky 382RL Air Conditioner

Hello Everyone,
I purchased a brand new 2014 Montana Big Sky 382RL last week. I went through the trailer at the dealership and immediately took it to the local KOA and plugged it in for the night as I had to pack for a trip the following day. The 5th wheel has two dometic 13.5 AC in front and 15 in back. The ceiling is a curbed ceiling with the return vents on the ceiling. The thermostat has capacity for four zones with two active 1 in the rear of the roof and one over the master bed room. The trailer never cooled down more than 5 degree below the outside temperature. The  airflow was very low also. The next morning I returned to the dealership all packed for our trip hoping the dealer would be able to diagnose the problem. After waiting an hour and a half they said the units were pulling 13.5 and they showed me that the duct design by keystone was actually very thin design molded into the curbed ceiling between the roof. The tech agreed there was a problem but he wasn't sure if it was the ducts or something else. Being that I was leaving on a 2k mile road trip I opted to leave it there and just stay in hotels on my trip (a real bummer and very expensive). I have heard from the dealer over the last week and they said they found some roofing material in the duct but it still doesn't seem to be effecting the airflow. I have searched online and found nothing mentioning problems with the big sky. This is the top of the line offering from Keystone in their Montana line. Has anyone experienced similar issues with these trailers?

Haven't heard other owners complain about that, but individual examples of any given model can vary a lot. Consistency of quality is NOT an attribute of any RV!

A/c performance is measure against inside air, not outside. Measure the difference in air temperature between the air intake side and the outlets. It should be at least 20 and hopefully 25. If it does that, the units are working properly. If not, more diagnosis needed. If the RV is not well insulated or has air leaks, it may be difficult to keep the interior well below the outside temperature, especially in full sun. That's a different problem than a/c performance.

Low air flow through the a/c system ducts reduces cooling (the RV gains heat as fast as the chilled air cools it) and often leads to a freeze-up of the a/c itself. The symptoms of a freeze-up (ice forms internally) or low air flow and limited cooling. If the a/c's start out fine but cooling deteriorates after 30 minutes or so, it may be icing up. One common cause of that is cold outlet air is getting sucked right back into the inlet (insufficient separation on the underside of the a/c). That usually can be fixed fairly easily once identified.

There is a Montana owners forum. I have asked many questions there and they have been very helpful!

Thanks for the information!