The liquid-filled PV breaker has acted to relieve a vacuum in a tank. What action must be taken in regards to the PV-breaker before continuing operations?

Correct Answer: Option A — Refill the breaker with liquid.

Liquid-filled pressure-vacuum (PV) breakers protect cargo tanks from over-pressurization or vacuum by venting through a liquid seal. When the breaker activates, the sealing liquid (usually water-glycol) is blown out. The breaker must be refilled to restore the liquid seal before resuming cargo operations.