Liquid refrigerant returning to the compressor during operation.
Floodback is liquid refrigerant reaching the compressor while it runs, typically from overcharge, a metering device stuck open, or low evaporator load (for example low airflow). It dilutes oil and can damage valves or scrolls. Low or zero superheat at the compressor is the warning sign. Slugging is the violent case where a mass of liquid enters the compression space.
Exam work areas
F · Maintenance, service and troubleshooting