Mine isn't as new as yours, hydro-Hot, but same principle. It depends on how cold it is outside, how much hot water is being used at the time. I run mine with both the diesel burner and electric element on. However, mine only runs for about a minute when the diesel burner turns off. So, 5 minutes sounds like longer then I would expect. I run the rear zone at a lower temp when not in use with the door closed and the front zone higher. So, I heat where I am the most. Usually the rear zone heats the basement, so don't turn it down to low.
Karl and Janet
Tiffin Zephyr 45QDZ
Owens-Classic Trailer, with elevator and air ride