[Trainer]

Chester,

The engine pre-heat pump in the Aqua Hot only pumps engine coolant, not Aqua Hot coolant. The engine coolant is circulated through coils (just like the fresh water heating coils) to pick up heat from the Aqua Hot coolant and warm the engine for starting in cold weather.

Conversely, while driving down the road, the engine driven coolant pump will circulate hot engine coolant through the engine pre-heat coils heating the Aqua Hot coolant. So you can heat the coach front to back by setting the interior thermostats to heat any zone you need warmed up. Really frigid conditions would need the diesel burner to help the hot engine coolant provide enough heat to warm up the interior.

Bob,

With switches off and fuses pulled, I do not know of what would be running in the Aqua Hot heater.

The basement thermostat will command pump 2 and the basement fan coil with the interior turned off. But I would expect it to not work with fuses pulled.