What is the purpose of a liquid line drier?

The purpose of a liquid line drier is primarily to remove moisture from the refrigeration system after evacuation. Moisture within the system can lead to various issues, including corrosion, decreased system efficiency, and potential damage to components such as the compressor and expansion valve. The drier contains desiccant materials that absorb moisture and also act as a filter to capture any particulate debris that might be present in the refrigerant.

By ensuring that the refrigerant is free of moisture, the liquid line drier helps to maintain the integrity and performance of the entire HVAC system. This is crucial for preventing ice formation, which can impede fluid flow and disrupt the cooling cycle.

The other choices deal with functions that a drier does not perform. Adding refrigerant to the system, filtering air, or cooling refrigerant before it enters the compressor are not roles attributed to a liquid line drier. Instead, these tasks are managed by other components within the HVAC system.