I agree that the engine coolant should circulate through the Aqua Hot and heat the boiler fluid anytime the engine is running. Mine does not seem to do so at a level that is useful. I threw that out there with the thought that if I have the problem, others probably do as well. It might be that mine is a fixable problem or it might be a design issue. For me the easiest solution has been to turn on the engine preheat. The preheat consists of a electric pump which is located in the engine coolant line which runs through the Aqua Hot. The pump is the only part of the engine preheat system that is unique to the preheat system. The balance of the system is used for both preheat and hot water/furnace heat off of the engine. Again, I can only speak for my coach and I agree that according to the book I should not have to turn this pump on when traveling.
If anyone has experienced the problem of limited circulation of the engine coolant using only the engine cooing system and been able to cure it, I would appreciate hearing about it.
I should mention that I do not seem to have cooling problems with the engine. It warms up in a reasonable fashion and runs between 185 and 195 degrees unless I am doing a major hill climb (like Vail Pass). In a major climb the oil temp spikes up, I think due to the turbo boosting at max which is followed by the engine coolant going to 214 or so. At this point I usually try to control the temp by increasing engine RPM, which usually also means slowing down a bit, and that seems to work well. I also think that when the temp spikes that fast it gets ahead of the dynamics of the cooling fan control. By the time I get to the top of the pass the cooling fan is catching up and the temp has stabilized back under 210.
Bruce
