What should you do when recovering refrigerant from a frost-free refrigerator?

When recovering refrigerant from a frost-free refrigerator, turning on the defrost heater is essential because it helps facilitate the recovery process. Frost-free refrigerators often have a build-up of ice that can hinder the proper flow of refrigerant. By activating the defrost heater, you can melt the ice and allow the refrigerant trapped within the system to flow more freely, aiding in more efficient recovery.

Leaving the fridge unplugged can prevent the compressor from operating, thereby limiting the refrigerant recovery. Checking for leaks is a good practice for overall system maintenance, but it doesn't directly contribute to recovering the refrigerant from the refrigerator itself. Disconnecting the compressor might limit access to the refrigerant but is not necessary for the recovery process and could lead to additional complications or risk of refrigerant release. Thus, turning on the defrost heater is the most effective and appropriate action during the recovery process for a frost-free refrigerator.