DPs are class A, too. But Oasis (and Aqua Hot) hydronic systems are, to the best of my knowledge, diesel only, and I've never come across such a system in a gasser. It could be done (from the factory, at least), with a separate tank of diesel or perhaps with an oversized propane tank, but I'd be leery of such a thing running on gasoline (seems a bit dangerous to me). Of course the expense (quite a few thousand dollars) would deter many folks, and I don't think the demand is there for such an expensive add-on to a gasser.