When working on a refrigeration system, technicians may occasionally come across one where the type of refrigerant is unknown. Either the system’s data plate is missing or unreadable, or the refrigerant has been changed out and the system has not been properly identified with the replacement refrigerant. Do not panic right away. Although this is an issue, the current system problem may not require knowing the refrigerant type. The failure might be electrical in nature or a maintenance issue such as a dirty coil.