Our Atwood furnace had smoke coming out of it the first time I turned it on, we did not use it anymore that first trip. It didn’t set off the propane or CO detector but the smoke detector was beeping before I realized it was even smoking.
I ran it when we got back home and the smoke stopped, but I was at over 5 hours of constant run time before I couldn’t detect any odors from it. I tried it again the next day and the odor was back, it was almost like a chemical smell.
After running it all day again at home the odor is gone, and I have run it on several trips without any problems.