Was looking around ulnit yesterday evening while doing a few "maintainance" projects trying to get unit ready for a real shakedown trip and looked inside the air return grill beneath the refrig. Is there supposed to be any type of filter behing the grill to filter return air before going to the furnace? Also noticed that there was a flex hose just lying on the floor with a fitting that looks lide it goes on one the holes on the left side of the unit (not hooked up). That is a project for this weekend as I'm sure it is supposed to be hooked up there - the hose ( 4" round) goes toward the front of the unit probably to underbelly or storage area.