Natural Draft Burner : A fuel-burning device that depends primarily upon the natural draft in a chimney or venting system to induce the air for combustion into the burner.
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}