Meaning of return-flue boiler

re•turn'-flue' boil"er

Pronunciation: (ri-tûrn'fl'), [key]
  1. a fire-tube boiler having flues that collect the combustion gases at the end of the boiler opposite the fire door and pass them through the boiler to an uptake above the fire door. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.