Referring to the illustration, suppose after initiating the oil discharge mode, the oily- water separator fails to come out of the oil discharge mode in a timely fashion. Cracking open the upper sampling valve reveals the presence of water exiting under a positive pressure. What is most likely the cause? GS-0175

Correct Answer: Option D — The upper oil/water interface detection probe fails to end the oil discharge mode.

The upper probe serves as the high-level sensor for oil accumulation. If it fails to detect the oil-water interface, the system will not receive the signal to terminate the oil discharge mode. Consequently, the discharge valve remains open, allowing water to exit under pressure instead of oil.