🔍 Key Concepts

• Oily-water separator operating modes: normal separation vs. oil discharge mode • Oil/water interface detection probes: how the upper and lower probes control starting and stopping oil discharge • System pressure paths: what provides positive pressure to push separated oil out of the separator

💭 Think About

• When you crack the upper sampling valve and see oil under positive pressure, what does that tell you about the level and location of the oil layer in the separator? • If the unit stays in oil discharge mode longer than it should, which component is responsible for signaling that the oil layer has dropped to the correct level? • Which of the listed failures would still allow oil to be present at the top of the separator and be under pressure?

✅ Before You Answer

• Identify which component actually terminates the oil discharge mode in this design (look at the probes and dashed control lines). • Determine what provides discharge pressure to the oil outlet in oil discharge mode and whether that pressure is obviously present from the description. • Eliminate any option that would prevent oil from reaching the top sampling point or from being under positive pressure there.