Furnace gas is aspirated through furnace gas conduits (44) to the low pressure throats (42) of the Venturi conduits (41) that move high oxygen content gas to the combustion chamber (28) of the aspirating burner (20). Fuel is injected through fuel conduit (46) to the combustion chamber (28) to mix with the gases and form the flame in the combustion chamber which is emitted at high velocity from the burner into the furnace.