Just caught up with this thread, and as much as I enjoyed the bickering, I have to make an observation. Other than factual errors (mostly minor) on the part of some of the posters, I think the biggest cause of disagreement here, like on so many threads, is many members' assumption that every unit made by X (in this case Aqua-Hot) works just like theirs. In this case, as many of us are aware, some AH units have the "motoraid" feature, while others (like mine) don't, and AH has used various types of coolants over the years.
The solution? Instead of saying "they all work like this," just say "mine works like this" (unless you're such an expert that you know the entire production history of the product). And/or, just take a chill pill, and don't get your feathers ruffled every time someone thinks (or knows) they know better than you!