I have a manual for the AP125HD. The information contained for the heat function is very vague. I've read several times and am unclear on how to set the temperature. The second question is does it need to be vented with both hoses? It operates in heat with the left side hose vented out. The right side with no hose just draws a slight bit of air from the room. So keep drapes/curtains clear of that. If anyone has a better explanation for setting up the temperature settings please post. Next step is to call for service for a lesson.