Air Conditioner Problems

[TTown]

I have a 2024 Entegra Ethos 20T. I live in Las Vegas and camp in mostly hot temperature.When it is over 90 my unit will no longer cool. I have had it into the dealer 4 times with no luck. They say that is how th manufacture has it set up. Has anyone else had this problem?

TTown

 

[Holdmybeer]

Unfortunately, if you're in direct sun on 90°+ days a 13.5k btu rooftop a/c will likely struggle in the late afternoon hrs. to cool even a class B. Just to be sure though I'd check the temp of the cooled air coming from the plenum. The air coming out should be 16-22° cooler than the air going in (return air).
Insulating the glass, especially the windshield and any glass facing West may help.