A purge system for removing contamination from a chiller system includes a purge chamber including a degassing membrane, the degassing membrane dividing the purge chamber into an inlet portion and an outlet portion, the inlet portion for fluid communication with the chiller system, the degassing membrane to pass contamination from the inlet portion to the outlet portion; a valve coupled to the outlet portion of the purge chamber, the valve providing an exit for contamination from the outlet portion of the purge chamber; and a controller to open or close the valve in response to pressure in the outlet portion of the purge chamber.