I just bought a used one, and it arrived damaged in more ways than one. That is not really the point.
After calling Sonofresco, I realize their support is great. I would just call them and they will help you troubleshoot.
Just an FYI, mine is setup for natural gas, but I have the presumably brand new propane part that originally came with it (it consists of a box and pipe with the hose connection). So if that is faulty, let me know, maybe we can work something out, as I don't see myself going from NG to Propane.
Chris