This water heater was installed in our mobile home by the previous owner. It suddenly just stopped heating water recently. So I was looking at the manual, and says on there that this model must not be installed in a mobile home, but doesn't say why. I called the Rheem technical support dept., and the person they had answering the phones there did not know why either. They had an untrained person on this phone line, and she wouldn't let me talk to a supervisor. She said it wasn't made for mobile homes, but did not know any more than that. Does anyone know why?