单项选择题
A.compressor damage from improper lubrication
B.refrigerant absorption by the lubricant
C.increased viscosity in the lubricant
D.carbon deposit on the compressor suction valves
单项选择题 Which of the valves listed is NOT considered to be a hydraulic system directional control valve?（）
单项选择题 Which of the listed refrigeration system components keeps the refrigerant circulating through the system?（）
单项选择题 Which of the listed components is considered to separate the high pressure side of a refrigeration cycle from the low pressure side of the cycle?（）