What should be done after reaching the required recovery vacuum on an appliance?

After reaching the required recovery vacuum on an appliance, it is important to wait for a few minutes to see if the system pressure rises. This step is crucial because a rise in pressure would indicate that there may be residual refrigerant left in the system or a potential leak. Allowing time for the vacuum level to stabilize ensures that you're confirming the effectiveness of the evacuation and that the system is truly devoid of moisture and non-condensables. This verification process is fundamental in ensuring that the vacuum achieved is not only valid but also that the system can be confidently charged without introducing problems that could arise from moisture or contaminants.

In contrast, proceeding with charging refrigerant immediately neglects this precaution and risks introducing issues into the system. Disconnecting all hoses and turning off the machine without performing this wait-and-check procedure may also lead to missing any potential leaks. While recording the vacuum level is part of good practice, it should not replace the critical waiting period for pressure stabilization. Thus, the practice of waiting ensures a more reliable and effective servicing of the refrigeration system.