return-flue boiler

[ ri-turn-floo ]
/ rɪˈtɜrnˈflu /

noun

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 re·turn-tu·bu·lar boil·er [ri-turn-too-byuh-ler, -tyoo-] /rɪˈtɜrnˈtu byə lər, -ˈtyu-/.

Origin of return-flue boiler

First recorded in 1885–90