I finally got the water heater working correctly. I found 2 service centers in Des Moines that are factory authorized to do warranty work on the water heater. One of them wouldn't get back to me and the other offered to get me in in 3 months....
I was working with a rep from Atwood, who couldn't do much more than try to put me in touch with a local repair center. They are the ones who gave me the 2 to try. When I let them know that one wouldn't return phone calls and the other wouldn't get me in in a timely manner, Atwood agreed to help me directly. They asked that I send the ignitor and control board back to them. They even paid the UPS shipping. Within 5 day I had a new control board and ignitor in my mailbox. I installed them this weekend and the heater works like a champ!! Fires right up, ignitor stops firing and the heater keeps running.
Took a little time, but Atwood made things right.
I never did hear from Atwood which part was causing the problem. Since they sent both, I guess it must have been a combination of the two.
2016 Coachmen Prism 2150LE