What might cause high suction superheat in a refrigeration system?

High suction superheat in a refrigeration system occurs when the temperature of the vapor refrigerant at the suction line exceeds the saturation temperature corresponding to the system pressure. This situation can be influenced by several factors, but when air infiltrates the refrigerant lines, it typically leads to an increase in superheat.

Air is an unwanted contaminant in a refrigeration system because it can reduce system efficiency and create issues such as elevated pressures and temperatures. When air is present, it does not condense and remains as a gas in the system. This results in an increased vapor content, which raises the temperature of the refrigerant vapor at the suction line. Consequently, the refrigerant takes in more heat from the surrounding components without a corresponding increase in pressure, leading to a higher suction superheat reading.

Understanding this phenomenon is crucial for diagnosing issues within refrigerant systems and highlights the importance of maintaining a closed system devoid of contaminants like air.