… air), not electrically heated, incorporating a motor-driven fan or blower, and parts thereof, of iron or steel. …
Explanatory notes
… air), not electrically heated, incorporating a motor‑driven fan or blower, and parts thereof, of iron or steel. … exchanger (tube assembly, etc.) which transfers the heat given off by the combustion gases passing through it to the air travelling along its outer surface, and a motor‑driven fan or blower. Generally these heaters are furnished …