| 165 / | HD | HEAT EXCHANGE |
| DIG 92 | DD | WITH VALVE OR MOVABLE DEFLECTOR FOR HEAT EXCHANGE FLUID FLOW {6} |
| DIG 126 | DD | .~ Total flow rate through heat exchanger controlled by valve {3} |
| DIG 127 | DD | .~.~ Stove pipe drum {1} |
| DIG 128 | | .~.~.~ Including air draft passage for heating ambient air |