Capillary tubes may become plugged due to what reason related to system oil?

Capillary tubes can become plugged primarily due to overheating of the oil in the HVAC system. When the oil experiences excessive heat, it can break down or degrade, leading to the formation of sludge or carbon deposits. This debris can obstruct the small internal passages of capillary tubes, which are designed to allow precise refrigerant flow. If the flow is restricted, it can adversely affect the system's operation, causing decreased efficiency and potential system failure.

Understanding the role of oil in refrigerant systems is crucial, as it acts as both a lubricant and a medium for heat transfer. If the oil is compromised due to overheating, it may not only block the capillary tubes but also reduce its effectiveness in lubricating the compressor, leading to premature wear or damage. Therefore, managing operating temperatures and ensuring proper oil maintenance is vital to prevent plugging and ensure the system runs efficiently.