What symptom may indicate a lack of refrigerant in a refrigeration system?

In a refrigeration system, a lack of refrigerant can lead to a continuous running of the compressor. When there is insufficient refrigerant, the system cannot efficiently absorb heat from the space being cooled, which causes the compressor to operate longer in an attempt to maintain the desired temperature. This behavior can lead to overheating, as the compressor struggles to perform its function without the necessary refrigerant to cool and circulate the system.

While the other symptoms might point to various issues within the refrigeration system, they do not specifically indicate a lack of refrigerant. Excessive water temperature could be related to other problems like blockages or improper settings, scaled coil surfaces may indicate poor maintenance or water quality issues, and oil leaks around the compressor could signify mechanical failure or wear, but not necessarily a refrigerant shortage. Hence, the continuous running of the compressor is a clear symptom indicating that there is insufficient refrigerant present in the system.