Here are the BTU possibilities from my owners manual, Atwood Hydro Flame 8500 IV LD series furnace. Problem is I have no clue what my model # is. But 30,000 dose sound familiar as to the BTU rating but not for sure.
8516- IV 16,000
8538 -IV 35,000
2004 Chevy 2500HD Crew Cab 6.0l, 4.10r
2010 Jayco Jayflight 28BHS
Reese Strait Line with Dual Cam
P3 Brk controller