A plug for regulating a flow of gas in a system is disclosed. The plug includes a housing disposed on a temperature boundary in a system. The housing defines a passage for flowing gas therethrough. The plug further includes at least one pressure-actuated valve disposed in the passage and movable between an open position and a closed position. The at least one pressure-actuated valve moves from the open position to the closed position as the pressure of the gas increases and moves from the closed position to the open position as the pressure of the gas decreases.