How to identify the btu of rooftop AC unit

sound right to me

15,000 BTU. Here's a link for you. http://www.dometic.com/FileOrganizer/1-international/Operation%20&%20Installation%20Manuals/Air%20Conditioners%20-%20Vehicles/Duo-Therm-HP_installation_EN.pdf

it sounds like no communication from stat to board. cable connections

You can use Dometic Brisk Air II model for your RV. It has 13,500 BTU capacity. I used this air conditioning unit for last 2 years on my RV truck. If you want to know more about this unit, you can check this link. https://coolingmyrv.com/

For an RV 15000 BTU air conditioner the size being maximum for 115 volts ac you will need to have a independent circuit breaker for it only and rated at 20 amps. The average amps depends on serveral factors like actual supply voltage somtimes 110 to 120 volts and wire size and length feeding the air conditioner. To answer your question the average Amps will be near 13 Amps. Click Here=>

Dometic RV Air Conditioner Installation Manual and Specifications
Click here for a photo of the Electrical Spects.=>

Dometic_RV_Air_Conditioner_Electrical_Specifications
If you have any questions I will be here to answer them for you, Thanks, Sea Breeze

Early years were R-22 but the best way to double check would be to contact manufacturer with model and serial number for confirmation.
( dometicusa.com ) for dometic products, or ( http://www.rvcomfort.com/rvp/tech_info/manuals.php ) for Coleman.

This is a 15,000 btu unit :-)

Your choices are another Dometic or a Coleman
I prefer the Coleman But the amount of extra cooling you will get by stepping up to a 15K unit will probability not be worth the added cost

well, have you checked the charge? are the condenser fins clean and clear?

59516 is a Brisk Air 15000 BTU.
Thanks for using Fixya
Jerry