Abstract: A burner apparatus comprising housing defining a chamber and having an air inlet, a peripherally extending baffle disposed in the housing, a first peripherally extending flow passage being formed between the housing and the baffle, the first flow passage being in open communication with the air inlet, a peripherally extending combustion liner disposed inwardly of the baffle, a second peripherally extending flow passage being formed between the liner and the baffle, the second flow passage being in open communication with the first passage, a reversing diverter disposed in the chamber and positioned to direct air flowing from the first flow passage into the second flow passage, a burner assembly mounting plate disposed in the liner and having a first side and a second side, the mounting plate and the liner at least partially defining a burner barrel on the first side of the mounting plate, at least one burner assembly mounted on the burner mounting plate and a plenum on the second side of the mounting plate th