U.S. Department of Energy - Energy Efficiency and Renewable Energy

Federal Energy Management Program – Operations and Maintenance

Air Compressor Maintenance

Maintenance of your compressed air system is of great importance yet it is often left undone or half done. Neglect of an air system will ultimately "poison7" the entire downstream air system and cause many problems. Clean, dry air supplies start at the air compressor package. The small amount of time you spend maintaining the system is well worth the effort.

General Requirements for a Safe and Efficient Air Compressor

  • Always turn power off before servicing.
  • Monitor compressor oil and oil cleanliness:
    • Change the oil according to manufacturer's recommendations.
    • Use a high-quality oil and keep the level where it's supposed to be.
    • Sample the oil every month.
  • Monitor condensate control:
    • Drain fluid traps regularly or automatically.
    • Drain receiving tanks regularly or automatically.
    • Service air-drying systems according to manufacturer's recommendations.
  • Keep air inlet filters clean.
  • Keep motor belts tight.
  • Minimize system leaks.

Common Causes of Air Compressor Poor Performance

Problem Probable Cause Remedial Action
Low Pressure at point of use Leaks in distribution piping Check lines, connections, and valves for leaks. Clean or replace filter elements
Clogged filter elements  
Fouled dryer heat exchanger Clean heat exchanger
Low Pressure at compressor discharge  
Low pressure at compressor discharge Improper adjustment of air capacity control (for systems with modulating load controls) Follow manufacturer's recommendation for adjustment of control
Worn or broken valves Check valves and repair or replace as required
Improper air pressure switch Follow manufacturer's recommendation for setting air pressure switch
Water in lines Failed condensate traps Clean, repair, or replace the trap
Failed or undersized compressed air dryer Repair or replace dryer
Liquid oil in air lines Faulty air/oil separtation Check air/oil separation system and change the separator element
Dirt, rust, or scale in air lines In the absence of liquid water, normal aging of the air lines Install filters at point of use
Excessive service to load per hour ratio System idling too much For multiple compressor systems, consider sequencing controls to minimize compressor idle time. Adjust idle time according to manufacturer's recommendations.
Improper pressure switch setting Re-adjust according to manufacturer's recommendations.
Elevated compressor temperature Restricted air flow Clean cooler exterior and check inlet filter mats
Low oil level Check compressor oil level and add oil as required
Restricted oil flow Remove restriction and replace parts as required
Excessive ambient temperatures Improper ventilation to compressor; check with manufacturer to determine maximum operating temperature.

Maintenance Checklist