An anesthesia vaporizer system having a reservoir fillable with anesthetic agent from a bottle. A fill body defines a cavity that receives the anesthetic agent from the bottle via an inlet. The fill body further defines main and vent ports each communicating between the cavity of the fill body and the reservoir. A fill valve is receivable within the cavity of the fill body and moveable between open and closed positions. The anesthetic agent from the bottle flows through the inlet only when the fill valve is in the open position. A lower seal is receivable within the cavity of the fill body and moveable between open and closed positions by the fill valve. The vent port communicates between the cavity and the fill body only when the lower seal is in the open position. The lower seal is positionable in the open position when the fill valve is in the closed position.