Which component is NOT a type of metering device?

The bare tube is not considered a type of metering device in HVAC systems. Metering devices, such as capillary tubes, automatic expansion valves, and thermostatic expansion valves, are essential for controlling the flow of refrigerant to ensure optimal cooling and heating performance.

Capillary tubes regulate refrigerant flow by using a narrow passage that causes a pressure drop as the refrigerant travels through it, allowing for proper expansion. Automatic expansion valves and thermostatic expansion valves also serve the critical function of adjusting the refrigerant flow based on pressure or temperature changes, maintaining system efficiency.

The term "bare tube" does not refer to a recognized metering function; rather, it generally indicates an uninsulated or unencased tube, which does not play a role in the control or regulation of refrigerant flow within HVAC systems. Therefore, selecting this option accurately identifies the component that does not fit within the category of metering devices.