Here is my opinion, after having used a Hardy for 14 years. You said the wood was still sitting there just like you put it in there. right?
Pine burns hot and fast, so I think it heated the water up so fast it shut the blower down before any coals could form. The water stayed hot long enough that the fire went completely out before the fan kicked back on. As others have mentioned you need a bed of coals all the time.
I don't know about the pine you have, but Missouri pine is not going to give you that. I burn a little of everything but I always make sure I have enough seasoned oak or hickory mixed in. to keep that bed of coals.
I also don't clean my ash pan completely out, I make sure the ashes stay below the grates, and leave ashes along the edges on top of the grates.