Which of the following is a good practice when operating a refrigeration system on a hot weekend?

In the context of operating a refrigeration system effectively, checking compressor oil levels is a fundamental practice, especially during periods of heightened demand such as hot weekends. The compressor is a critical component of the refrigeration system, and proper lubrication is vital for its optimal operation. Insufficient oil can lead to increased friction, overheating, and could ultimately cause system failure.

Ensuring adequate oil levels helps maintain the efficiency and longevity of the compressor, allowing it to handle the increased load typically seen during hotter days. Regular checks can also help identify potential issues before they escalate into significant problems, thereby minimizing the risk of equipment failure.

While the other options may seem relevant in certain contexts—such as turning off unused systems or increasing temperature setpoints—checking compressor oil levels remains a crucial maintenance step that directly affects the performance and reliability of the refrigeration system under stress.