What is a common characteristic of systems with a capillary tube?

Systems equipped with a capillary tube possess a common characteristic of having limited refrigeration capacity. Capillary tubes are fixed orifices that control the flow of refrigerant by acting as a metering device. Unlike expansion valves that can modulate the flow based on varying conditions, capillary tubes provide a constant flow rate, which is determined by the size of the tube and the pressure differential across it.

This fixed nature inherently limits the system's ability to handle varying loads effectively. Due to the single, unchangeable flow rate, when cooling demand increases beyond what the capillary tube can provide, the system may struggle to meet the higher capacity needs. Conversely, in low load situations, the capillary tube may not sufficiently restrict the flow, leading to issues such as flooding of the evaporator. This characteristic makes them less versatile compared to more advanced systems that utilize expansion valves or other variable metering technologies, which can adjust to different operating conditions and demand levels more effectively.