| 165 / | HD | HEAT EXCHANGE |
| 200 | DF | WITH TIMER, PROGRAMMER, TIME DELAY, OR CONDITION RESPONSIVE CONTROL {14} |
| 201 | DF | .~ Having heating and cooling capability {13} |
| 234 | DF | .~.~ Control of static pressure of conditioned space {1} |
| 235 | ![]() | .~.~.~ Space is within aircraft |