I'm not that familar with the Reddy heaters but there should be something that senses the flame. It probably needs cleaning. Look in the area where the flame is. I may be a small metal rod with a wire attached to it. This type will be located so that it is in the flame. You can clean it with some steel wool. I don't think it would have UV or cad cell type sensor which see the flame and wouldn't be located in the flame but would be close enough to "see" it. This type could just be wiped off with a cloth. Hope this helps.