Which of the following is a sign of potential compressor failure?

Abnormal noise levels during operation can indicate potential compressor failure because such noises often suggest mechanical problems within the compressor or issues with its components. In a properly functioning compressor, sounds should typically be consistent and within expected ranges. If there are unusual sounds—such as grinding, clanking, or excessive rattling—it may indicate wear and tear on the internal components, such as bearings or pistons, or even issues like refrigerant leaks or blockages. Monitoring these noise levels is crucial, as they could be early signs of a failing compressor that, if not addressed, could lead to more extensive damage and costly repairs.

Continuous operation without temperature change may suggest a failure in the system's ability to transfer or maintain refrigerant flow, rather than directly implicating the compressor itself. Frequent starting and stopping could be a result of various issues, including electrical problems or thermostat settings, rather than solely pointing to compressor failure. Vibration during operation can result from multiple factors and may not necessarily indicate a compressor problem without further context. Thus, while these signs are relevant in assessing system health, abnormal noises are the most direct indicator of issues specifically associated with compressor integrity and functionality.