Thermodynamics of air and liquids are different. If he is trying to do this on an egg... the egg will be 700 degrees before the water hits 150 and try taking an egg from 700 to below 150 (to drop the temperature when it sails past 150) by controlling draft.
Q-Dat, I am not an egg head. Done it on a drum, small diameter, tall fire basket. Diffuser plate would be an asset.