I'm thinking of replacing a wall furnace in my workshop thats over a detached garage with a small condensing furnace. I don't have a proper drain in it but I do have a 2" line roughed in that I could dig some sort of small dry well for. Lots of work, and I'm afraid it might freeze solid in really cold weather. I'm in Chicago. I really don't want to dump a drain out the side wall of the garage either as a contractor suggested, it's a very handsome coach house. So here's the question, how much water will a 45K BTU furnace, mostly set at 50 degrees make? Can I possible drain it to a 5 gal bucket and empty it once a week or so? And guy's no please snide comments about being a hack, it's a garage workshop for pete's sake!