🔍 Key Concepts

• Compound gauge (pressure/vacuum) on a bilge water separator inlet (item "1") • What it means when a gauge reads 0 psig (relative to atmospheric pressure) while there is water available at the suction (1 ft in the bilge) • Typical pressure indications when the separator is pumping/processing versus when it is shut down or in a different mode

💭 Think About

• If the pump were actually moving bilge water through the separator, what kind of pressure or vacuum would you expect the compound gauge at the top of the separator to show? Would it likely be exactly at 0 psig? • Does a 1‑foot water level in the bilge by itself guarantee pressure at the separator inlet, or does the reading on the compound gauge tell you more about whether the system is doing any work? • Which of the listed modes (oil discharge, processing, damaged, not turned on) would most realistically coincide with a perfectly neutral pressure (0 psig) at the separator’s compound gauge?

✅ Before You Answer

• Confirm that 0 psig means the internal pressure is the same as atmospheric pressure (no suction and no positive pressure). • Decide whether a properly operating separator that is processing bilge water should show some positive or negative (vacuum) pressure on this gauge rather than exactly zero. • Consider whether a damaged gauge or a unit in oil discharge mode would necessarily read 0 psig, or whether the simpler explanation is that the system is not creating any pressure differential at all.