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What does it mean to pull a vacuum in a refrigeration system?

  1. Raise the pressure level

  2. Stabilize the pressure

  3. Lower the pressure below atmospheric

  4. Introduce noncondensable gases

The correct answer is: Lower the pressure below atmospheric

Pulling a vacuum in a refrigeration system means lowering the pressure below atmospheric pressure. This process removes any noncondensable gases and moisture that may be present in the system, ensuring optimal performance and preventing potential issues like reduced efficiency or component damage. Stabilizing the pressure or raising the pressure level would not achieve the same goal of evacuating the system of unwanted gases and contaminants, making these options incorrect. Introducing noncondensable gases would be counterproductive to the vacuum process, as the goal is to remove such gases from the system.