Floodback occurs when liquid refrigerant returns to the compressor during the running cycle. Often a service contractor may see a compressor that failed due to floodback, but because of the severity of the damage, he may misdiagnose the problem. System-based causes of slugging and floodback may be different from each other; finding the root of the problem is essential to prevent it from happening again.

There can be multiple system causes of floodback, even as basic as lack of airflow because the system's filter has not been changed. It also may be a problem with the expansion valve, but then again, it may not be. A contractor or service technician should never jump to this conclusion. The metering device may lose control, but this does not mean that the root of the liquid floodback was a metering device problem. For instance, if the evaporator coil freezes over, if an evaporator fan fails, the liquid will not be properly evaporated. This liquid then returns to the compressor, and the result is severe damage or failure due to floodback.

Depending on the style of compressor, an observant contractor or service technician will see different failure patterns. These are observable by performing a compressor teardown yourself or by sending it to the manufacturer and requesting them to perform a teardown. Some (not all) compressor manufacturers will send back the results of such a teardown. By determining the failure patterns within the compressor, a service contractor can do a better job of determining what types of system problems may have led to the compressor's damage.