Final answer:
When a refrigeration system needs to be opened and repaired, it can be done without recovering the refrigerant to the required vacuum level by isolating the section that needs repair and utilizing shut-off valves or service valves to close off the refrigerant flow.
Step-by-step explanation:
When a system needs to be opened and repaired in a refrigeration system without recovering the refrigerant to the required vacuum level, it is typically done by isolating the section of the system that needs repair and using shut-off valves or service valves to close off the refrigerant flow. This prevents the loss of refrigerant from the system, allowing the repair to be made without the need for recovering the refrigerant to a vacuum level. Once the repair is completed, the system can be opened and the shut-off valves or service valves can be reopened to restore the refrigerant flow.