Compressors, Condensors, and Evaporators These are essential elements of air conditioning and refrigeration systems. Several compressor units of different sizes are likely to be present for the air conditioning, walk-in coolers and freezers. The compressor is often the component that breaks down in these systems. Condenser breakdowns are most frequently caused by a breakdown of the unit's fan motor. Fouling of the unit's coils causes a large percentage of evaporator breakdowns. Air conditioning and refrigeration systems are integrated, so problems with one part can lead to trouble with another. For instance, fouled evaporator coils can create conditions that lead to a subsequent compressor breakdown. © 2004 The Hartford Steam Boiler Insurance and Inspection Company.     All rights reserved.