| 126 / | HD | STOVES AND FURNACES |
| 569 | DF | SOLAR HEAT COLLECTOR {18} |
| 634 | DF | .~ With means to convey fluent medium through collector {7} |
| 635 | DF | .~.~ Having evaporator and condenser sections (e.g., heat pipe) {1} |
| 636 | DF | .~.~.~ Particular fluid {1} |
| 637 | | .~.~.~.~ Gas |