| 165 / | HD | HEAT EXCHANGE |
| 200 | DF | WITH TIMER, PROGRAMMER, TIME DELAY, OR CONDITION RESPONSIVE CONTROL {14} |
| 201 | DF | .~ Having heating and cooling capability {13} |
| 253 | DF | .~.~ Temperature sensor controlling temperature {4} |
| 254 | DF | .~.~.~ System selects heating or cooling mode automatically (e.g., responsive to season, ambient light, temperature in conditioned area, etc.) {5} |
| 255 | ![]() | .~.~.~.~ Dead band between heating and cooling |