During a system operation using R134A, what does the system indicate if the suction pressure falls to 15 psi and then into a vacuum?

A suction pressure dropping to 15 psi and into a vacuum indicates a situation where the refrigerant is not functioning properly within the system. One of the main causes of this issue can be the presence of moisture within the refrigeration system. When moisture enters the system, it can lead to the formation of ice in the evaporator or other components, which restricts the flow of refrigerant and ultimately causes the suction pressure to drop. This kind of pressure reading suggests that the refrigerant is having difficulty circulating, which is a strong indicator of moisture contamination.

In addition, proper functioning of the refrigeration system is characterized by specific pressure levels corresponding to the refrigerant being used, and a significant drop like this suggests malfunction. Hence, the condition of moisture being present is a relevant concern and aligns with what the readings indicate.