| Rating | Solver | Clue |
|---|---|---|
| KETTLES | Water boilers | |
| URNS | Water boilers | |
| FEED | The water supplied to steam boilers. | |
| FEEDER | A device for supplying steam boilers with water as needed. | |
| FUR | The deposit formed on the interior of boilers and other vessels by hard water. | |
| ECONOMIZER | Specifically: (Steam Boilers) An arrangement of pipes for heating feed water by waste heat in the gases passing to the chimney. | |