I think it's a 7912III but I'm going off memory. Roughly 20,000BTU with electronic ignition. It heats fine and runs fine - especially after buying a new motor and plastic cage fan for it (man does it run quiet and smooth now). But I noticed after our last outing quite a solid bit of black soot on the side of the camper. now to be fair we had driving sleet and wind and the damn thing ran for something like 30 hours straight to get that soot. You could smell the exhaust a bit inside as well. I'm not overly worried, but it just made me wonder if there's a service interval for these things or if I need to be thinking about a new gas valve for it? I'm camping this weekend. It's supposed to be 17 on Friday night. WTH am I thinking?