Compressor and Condenser Compressors and condensers are essential elements of air conditioning and refrigeration systems. Several compressor units of different sizes are likely to be present for the A/C, walk-in and freezers. The compressor is often the component of such systems that breaks down. It also can be the most expensive to replace as both the labor and component costs are high relative to other parts of such systems. Most air conditioning or refrigeration system breakdowns are a result of either electrical breakdown of the driving motors, or mechanical parts breaking in the compressor. Condenser breakdowns are most frequently caused by breakdown of the unit's fan motor. © 2004 The Hartford Steam Boiler Insurance and Inspection Company.     All rights reserved.