| 165 / | HD | HEAT EXCHANGE |
| DIG 92 | DD | WITH VALVE OR MOVABLE DEFLECTOR FOR HEAT EXCHANGE FLUID FLOW {6} |
| DIG 123 | DD | .~ Heat exchange flow path through heat exchanger altered (e.g., crossed, etc.) {1} |
| DIG 124 | DD | .~.~ Stove pipe drum {1} |
| DIG 125 | | .~.~.~ Valve mounted on fixed deflector |