I remember posting something about another (or the same?) SA paraffin geyser some time ago. Crispin, have you seen this one? It ought to be a fairly easy to adapt a number of different wood/biomass burner designs to this type of boiler. http://www.cbuying.co.za/index.php/paraffin-geyser http://www.slideshare.net/GreatNews/paraffin-water-geyser