Gravity or harvest-assist push-pins help the ice sheet fall off the evaporator and into the ice storage bin. Once the hot gas gives up its heat to the ice sheet, it may change to a liquid if enough heat is lost to the ice. A suction line accumulator is usually placed in the suction line before the compressor to protect the compressor from slugging and/or flooding. (See Figure 1.)
During the harvest mode, the receiver gets a mixture of hot gas from the compressor's discharge line and liquid from the condenser. A head pressure control valve located between the condenser and receiver (Figure 2) mixes the hot gas and condenser liquid, ensuring that the vapor from the top of the condenser is warm enough for defrost purposes.