Why is it recommended to remove oil from a low-pressure system at a temperature of 130°F?

Removing oil from a low-pressure system at a temperature of 130°F is recommended primarily because it ensures that less refrigerant is contained in the oil. At higher temperatures, refrigerants are less likely to dissolve into the oil and remain mixed with it. This allows for a more efficient extraction process, minimizing the likelihood of leaving behind a significant amount of refrigerant within the oil that could lead to system inefficiencies or operational issues once the oil is returned to the system.

Maintaining a higher temperature during oil removal helps in preventing any refrigerant trapped within the oil from causing issues, such as potential phase changes that could complicate servicing or degrade system performance. This practice ensures a more thorough and effective removal of oil, which is crucial for the health and efficiency of low-pressure systems.