Final answer:
Leaky valves in a refrigeration compressor can lead to noise, bubbles in the sight glass, rapid motor cycling, and abnormal discharge pressures.
Step-by-step explanation:
The symptoms of leaky valves in a refrigeration compressor can include a noisy compressor, the presence of bubbles in the sight glass, the motor starting and stopping rapidly, and the compressor operating at either low or high discharge pressure. A noisy compressor can indicate that the valves are not sealing properly, causing gases to leak during compression. Bubbles in the sight glass may suggest that the refrigerant is not being condensed fully due to a lack of pressure from failed valves. Rapid starting and stopping of the motor, known as short cycling, can also be a sign of pressure issues in the system. The compressor operating at low discharge pressure might mean the valves are not maintaining adequate pressure, whereas high discharge pressure could result from the valves not allowing the refrigerant to flow properly.