What is a common sign of an undercharged refrigeration system?

An undercharged refrigeration system often leads to an uneven frost pattern or excessive frost on the evaporator coil. This occurs because there isn't enough refrigerant to absorb the heat efficiently across the entire surface of the coil. As a result, certain areas may become overly cold, leading to excessive frost in those spots, while other areas may remain warmer and show little to no frost. This uneven thermal transfer is a hallmark indicator that the system is not operating at optimal refrigerant levels.

While other options might also present symptoms in a refrigeration system, they do not specifically indicate an undercharged scenario. The consistent evaporator coil temperature is typically associated with proper charge levels or overcharging. High pressure in the condenser is usually indicative of an overcharged system or airflow issues. Rapid cycling of the compressor can result from various factors, including system overload, but is not exclusive to undercharging. The uneven frosting directly correlates with the lack of sufficient refrigerant, making it the most definitive sign of an undercharged system.