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Extending Compressor Life Through Preventive Maintenance

Compressor failures are one of the most costly repairs to an air conditioning system. It is rare for the compressor to fail simply due to the compressor itself. Usually a compressor failure is symptomatic of another problem with the AC system (more on this in a later Service Matters).

The most common failures usually result from:
  1. Refrigerant floodback
  2. Contamination
  3. Lack of lubrication
  4. Electrical problems
  5. Overheating
  6. High head pressure


With some basic and proper preventive maintenance, your compressor life can be lengthened. Some of the preventive maintenance tasks will differ based on the type of system, but here are the basics:

  • 1. Keep coils clean
    • Dirty condenser coils reduce heat transfer in the system. This causes both temperature and pressure to rise, which not only results in system inefficiency, but over time can lead to compressor failure.

  • 2. Keep air filters clean and changed as required by site conditions
    • Dirty air filters contribute to dirty coils.

  • 3. Check suction and discharge pressures
    • Improper refrigerant charges can damage the compressor. Low suction pressure can cause refrigerant floodback.

  • 4. Verify proper operation of thermostatic expansion valves
    • If the TXV sensing bulb is loose or the setting is incorrect, refrigerant flooding can occur, damaging the compressor.

  • 5. Review fan controls
    • A lack of proper air flow across the evaporator cooling coils means less heat is available to vaporize all of the liquid. This can lead to refrigerant floodback, causing damage to the compressor.

  • 6. Check the amp draws on the system
    • High amps can cause the motor to overheat, resulting in compressor burnout.

  • 7. Check electrical components
    • Compressor contactors and starters must function properly. Single phasing, or constant starts and stops can lead to compressor burnout.

  • 8. Vibration analysis
    • Excess vibration could be a sign of internal damage inside the compressor, causing premature failure.

  • 9. Oil maintenance/oil analysis
    • Performing an oil analysis can identify moisture, contamination or possible bearing failure. Follow manufacturer’s recommendations on the proper oil, and never use additives.

  • 10. Check compressor safety devices
    • Oil pressure safety switches, low pressure control, and head pressure control devices give potential failure protection if operating properly.

The compressor is, in many ways, the heart of your air conditioning system. Proper maintenance can lead to a longer compressor life and a more reliable and more efficient system.

Speer Mechanical prides itself on providing building owners and supervisors with regular, maintenance advice to keep their buildings operating smoothly and efficiently. Follow these 10 tips, and discover a difference in your AC system operation.

Need more information?

Jim Hangen 614.261.5149

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