ESCO Air Conditioning Practice Exam

An increase in head pressure causes an equal amount of refrigerant to flow through a capillary tube. This is because the flow of refrigerant through a capillary tube is mainly determined by the pressure difference between the high side and the low side of the system. When the head pressure increases, the pressure difference across the capillary tube also increases, leading to a consistent flow rate of refrigerant. Therefore, option A is the correct answer.