Find the display panel for your Aquahot and look for red leds lit when the system should be heating or providing hot water. The diesel burner needs to be on and working properly to provide continuous hot water. If as stated before the stir pump has failed, hot water temperature will be highly variable. As for the front not getting heat, if that zone pump is out or the check valve is stuck the floor register can't deliver heat. Does the fan in the floor register come on? If the problem is in the 2015 Monaco in your original post, that is the time frame that Aquahot was shipping units with failure prone pumps. We've replaced all 4 Aquahot pumps in our rig built in August 2015.
HTH,
Art