I have an older camper with the Duo Therm furnace, model 65925-044. It will not stay lite. The camper is old, but new to me and has been sitting for a few years. IF and when it does light, the burner may, or may not light, but in a short time - 10 minutes to an hour - will go out. It is not windy out when this occurs so I don't believe it to be the weather. Any ideas? I was thnking of changing the regulator. Is this a good or bad approach to this problem? Where can one get parts for this model furnace? Any and all suggestions appreciated.