Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Components (hierarchy name)
4. components (objects parts)
5. [components by specific context]
6. system components
7. HVAC components
8. [cooling, heating and humidifying components]

Anotations

Scope note:

Automatic apparatuses for regulating temperature, particularly such a device in which the expansive force of metals or gas acts directly upon the source of heat, cooling, ventilation, or the like, or controls them indirectly by opening and closing an electric circuit.