Cabin Atmosphere Control Systems (1) A small amount of water in a vapor-cycle cooling system can freeze in the receiver-dryer and stop the entire system operation. (2) Water in a vapor-cycle cooling system will react with refrigerant to form hydrochloric acid which is highly corrosive to the metal in the system. Regarding the above statements, a. only No. 1 is true. b. only No. 2 is true. c. both No. 1 and No. 2 are true.