The difference between liquid over feed and flooded ice production systems comes down to the method for managing flow of liquid refrigerant into an ice maker and how the system is designed to prevent liquid refrigerant from getting back to the compressor.

For a liquid overfeed system, the liquid is continuously pumped into the ice maker from the recirculator during the freezer cycle and is typically overfed into the system at a rate of 3:1 (3 times more refrigerant than required).  The liquid refrigerant and gas exit the ice maker and go back to the recirculator vessel which is designed to separate the liquid and gas.  The liquid is collected in the vessel and pumped back into the ice maker. The gas then goes to the compressor to complete the refrigeration cycle.

For a flooded system, a float is used to maintain the liquid refrigerant at a level in the ice maker where mostly gas and very little liquid refrigerant exits the ice maker.  This gas and minimal liquid refrigerant mixture then exits the ice maker and goes to a suction accumulator that separates any liquid from the gas.  To get the liquid that accumulates out of the suction accumulator you either utilize a boil out coil inside the accumulator or you use a transfer system to send the liquid that accumulates back to the receiver.