Which component is critical for protecting the compressor from overheating?

The component that is critical for protecting the compressor from overheating is the overload relay. The overload relay monitors the current flowing to the compressor and disconnects power if it detects excessive current, which could be caused by various issues such as a clogged filter, low refrigerant levels, or a mechanical malfunction. By interrupting the power supply during these issues, the overload relay helps prevent the compressor from overheating and sustaining damage, ensuring its longevity and reliability.

In the context of the other options, while capacitors assist with the starting torque and overall functionality of the compressor, they do not provide protection against overheating. The expansion valve regulates refrigerant flow but is not involved in the protection of the compressor. Similarly, the filter drier is essential for removing moisture and particles from the refrigerant to maintain system cleanliness but does not directly protect the compressor from overheating. Hence, the overload relay is specifically designed to monitor and mitigate risks of compressor overheating, making it the essential component for this protective function.