I know this has been taked about before but I am not sure still if I have this correct? I have 300 Gal. water started with it at 100*, I ran my boiler [Gasser] for 1 hour and 20 minutes to get water up to 190*, with some hot coals left over, The wood is ash,chuncks kilm dried. at 55lbs of it. I built this myself so not sure of BTU. or anything, just it works very GOOD. Can anyone figure this or tell me where to look for methed to do it?