Vent valve assembly

Disclosed is a vent valve assembly (1) comprising a movable closure member (12) by manual admission of a working space (2) from a pressure sink separating the closed position can be switched with the pressure sink linking open position into a this working chamber (2). The movable closure member (12) is formed integrally with a pressure indicator device (35) that is able to visualize at least one in the monitored fluid space (36) pressure prevailing condition in from outside of the vent valve assembly (1) visible manner.