WW-F-2743, FEDERAL SPECIFICATION: FURNACES, WARM AIR AND HEATERS, UNIT, FORCED AIR CIRCULATION, OIL - AND GAS-FIRED (31-OCT-1989)

WW-F-2743, FEDERAL SPECIFICATION: FURNACES, WARM AIR AND HEATERS, UNIT, FORCED AIR CIRCULATION, OIL - AND GAS-FIRED (31-OCT-1989)., This specification covers self-contained, forced-circulation, air heating units designed to distribute warm air for heating purposes either through a duct system for central furnaces or by direct diffusion for unit heaters.