The Preair ALGR dehumidifier uses a refrigeration system that removes moisture from incoming air and adds heat to the discharged air. Hot, high-pressure refrigerant gas is routed from the compressor to the condenser coil. The refrigerant is cooled and condensed by transferring heat to the air about to be discharged from the unit. The refrigerant liquid then passes through a filter/drier and capillary tubing, which causes the refrigerant pressure and temperature to drop. It next enters the evaporator coil, where it absorbs heat from the incoming air and evaporates. The evaporator operates in a flooded condition, which means that all the evaporator tubes contain liquid refrigerant during normal operation. A flooded evaporator should maintain constant pressure and temperature across the entire coil, from inlet to outlet. The mixture of gas and liquid refrigerant enters the compressor after leaving the evaporator coil. The compressor evacuates the cool refrigerant gas from the accumulator and compresses it to a high pressure and temperature to repeat the process. When the indoor humidity reaches the set target value, the built-in humidity sensor of the machine can recognize it, and this cycle will automatically stop.