Which of the following is commonly tested for success during routine maintenance?

Compressor performance is a critical aspect often tested for success during routine maintenance. The compressor is the heart of the refrigeration system; it is responsible for compressing the refrigerant and circulating it through the system. Assessing the performance of the compressor includes checking for proper pressure levels, temperature fluctuations, and any unusual noises that might indicate wear or malfunction. Ensuring that the compressor operates efficiently helps maintain the system's overall performance and prolongs its lifespan, preventing costly breakdowns.

Focusing on the other options, while knowing the refrigerant type is important for servicing and compliance, it is not typically assessed as a performance metric during routine maintenance. Condenser size, although necessary for effective system design, does not change and therefore wouldn't be a routine test parameter. Lastly, the fan blade color has no bearing on operational effectiveness or efficiency, making it irrelevant to the assessment of routine maintenance success.