Originally Posted by Jamestn
I think it is kind of weird that there is vents that work no matter what unit is on but a few that only works depending on which unit is on. By the way, my unit only has 3 vents in living room. The is two vents on the side closest to the kitchen but only one vent near front of camper. This vent is between the 2 sofa's.
Not really that weird, the conventional layout described by Dometic is basically a double 'H', meaning long vent runs on either side of the rig with the two A/C units in the middle feeding both runs. With that setup, either A/C will blow cool air thru all of the vents. However, it isn't uncommon for the RV manufacturer to break one of the runs, especially in fifth wheels due to the roof transition and other roof obstacles like vent pipes, shower skylight, etc.
On my Cruiser, there is the second short run off the main A/C but none off the bedroom A/C. With a total of 5 vents and just 3 on the common run, this layout does not meet Dometic's specifications. According to Dometic such deviations require approval from Dometic. I requested proof of such approval from both Dometic and Crossroads with no response from either. This is just another reason so many owners experience inadequate cooling.