Which of the following is a sign that a low-pressure system might have a leak?

A low-pressure system having a leak can indeed be indicated by several signs, including significantly reduced refrigerant levels, increased compressor noise, and excessive oil residue.

Significantly reduced refrigerant levels are a primary indicator of potential leaks because a decrease typically indicates that the refrigerant is escaping from the system. If the refrigerant levels drop below the optimal threshold, the system may not operate efficiently and could lead to further issues.

Increased compressor noise can also be a sign of a leak. When refrigerant levels drop, the compressor may struggle to maintain the necessary pressure, leading to increased strain and noise. This change in sound often serves as an early warning signal that something is amiss within the system.

Excessive oil residue can be another clear sign of a leak. Refrigerants often carry oil, and when a leak occurs, the oil can escape along with the refrigerant. Areas around fittings, joints, or other connections may show signs of oil accumulation, signaling that refrigerant is likely escaping from that point.

Each of these indicators points to possible leakage and highlights the necessity of investigating the system further to determine the specific issue. Thus, recognizing all these signs aids in diagnosing and ensuring the proper functioning of a low-pressure system.