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

After reaching the required recovery vacuum on an appliance, it is essential to wait for at least a few minutes to see if the system pressure rises. This step is crucial because it allows you to confirm whether or not the system is holding the vacuum. A rising pressure may indicate a leak or that residual refrigerant is still present in the system. By giving it time, you can ensure that the vacuum is stable before proceeding with other steps, such as reconnecting or servicing the appliance. This practice helps ensure that the recovery process is completed properly and that the system is adequately evacuated before it's put back into operation.

The other options do not implement the recommended procedure for verifying the integrity of the vacuum achieved in the system. Disconnecting the recovery unit immediately could lead to inaccurate results regarding the vacuum's stability. Opening the system prematurely could allow more refrigerant to enter the system, undermining the recovery effort. Replacing the vacuum pump is not necessary after reaching the required vacuum unless there are performance issues; it does not address the critical step of verifying the vacuum's stability.