Heres what I've done so far.
I've removed all external appliances from the pack (heater core, pump, air pump) and the breaker still trips. I disconnected the main power wires from the pack and the breaker stayed on indicating that there is no short from the breaker to the pack itself. My feeling is that there is moisture behind the main board, where I can't see, or that the main board is fried, or lastly the breaker died. The problem is that replacing either item is a money sink. Especially if I'm wrong.
I'm hoping that its just water on the board that I can't see, and when it dries all will be right again. Is there a way to test the breaker to see if that could be the problem? Any advice?