If item "1" shown in the illustration is a compound gage indicating zero psig and the water level in the bilges is one foot high, the unit is __________. GS-0153

Correct Answer: Option D — not turned on

A compound gauge reading zero psig while the bilge contains water indicates the system is not pressurized. Since the oily-water separator requires an active pump and internal pressure to process bilge water or discharge oil, a zero reading confirms the unit is powered down or in a standby state.