Dwight, I assume you are carrying a full tank of fuel, since this is the optimal way to store your rig. If not, keep in mind the generator and AquaHot fuel pickups are set well above the tank bottom so they can't run you dry and prevent engine starting; always stay at least above a quarter tank.
That area covered, did the dealer provide information as to how recently the AquaHot received routine maintenance, such as filter change, nozzle changeout, and carbon cleaning?
And I assume you've reset the unit by switching off the diesel burner switch for a minute or two, then back on.
There are a couple of BAC members that are AquaHot-trained, contribute here on the Forum, and may have some thoughts for you.
And finally, a hearty welcome to the BAC. You will enjoy it!
Joel