A gas liquid separator system for a hydrogen generating apparatus includes a collection area for collecting liquid from the generated gases. To empty the collection area occasionally so that liquid does not build up and become entrained again in the dried gas, a vent solenoid is provided in communication with the collection area and a pump is used to create a vacuum periodically on the electrolysis cells. Such arrangement is used to open the liquid gas filter and possibly just the sump to atmosphere occasionally and vacuum generated to draw the liquid from the sump back to the electrolysis cells.