Which of the following statements represents the proper criteria to decide when to drain a filter/moisture separator as used in a ship's service air system hose station?

Correct Answer: Option C — The bowl should be drained before the moisture level reaches the lower baffle.

Filter/moisture separators must be drained before the liquid level reaches the lower baffle. If the moisture level rises above the baffle, the high-velocity air passing through the unit will re-entrain the collected water, carrying it downstream into the pneumatic tools or controls, which defeats the purpose of the separator.