AC upgrade / Need owners manual

In an RV that size I’m not sure a 1500 BTU upgrade will make that much difference.

Need a brand and model#

If I had a manual and brochure for it, I could tell you. I know it’s a Dometic 13.5k.

Ok for rooftop air conditioners generaly one manual covers multiple models So.
Dometic rooftop air conditioner manual... that was my google search

Click here

Odds are that's the right one but if you can get the model you can go to the dometic manual archive for an even better look.

To find model number method one
Remove lower grill and look up you may find a sticker showing the model. size and power needs

Method 2: up on the roof. Remove the shroud (you need to do this for cleaning anyway) clean the condenser (Fan side) while up there. again you may find the sticker.

Hopefully still readable.

Was the result

Here is
Interactive owners manual

ANY Roof RV Dometic will fit your RV. When you purchase the upper unit, that is all you get. You use your existing Tstat and wiring and control box. Doug

PS, EXCEPT the Penguin HP model

Pull off the lower cover and inspect to see that your cool air is going where it is supposed to. Make sure that it is sealed properly and all cool air is going in to the duct system and not in to your roof structure.

1. ONE AC will NOT cool your 30 ft Motorhome
2. a 15k will help, but you need 2 roof top units. What I would do is, usually the RV is wired for the 2nd bedroom AC unit. Install the NEW 15k in the Living room and install the 13.5 in the bedroom. IF you have 50 amp service, you will have no problems running them both. Doug

I had a rental fleet and all my class C over 26 feet long had a second AC installed. We put a Atwood Air Command and wired it independently from the RV wiring, so you could plug it on the 15 amp on the pedestal. In a pinch, I could plug it in the RV and run both ACs, but you had to be really carefull

Going from 13,500 to 15,000 is only a 9% increase in cooling so don't expect much.