What does the gas ballast control do?
The gas ballast valve controls the amount of air injected between the first and second stage of the pump. This is useful for driving condensable vapors (usually water vapor) out of the pump. For applications where a large amount of vapor is being pumped such as freeze drying or liphilization, running the pump with the gas ballast open for an hour every day will help keep the pump free of water and extend oil change intervals.
