Signs of a Failing Air End
Many air end problems develop as a result of service neglect or service adjustments due to changing operating environments. Take a closer look at the most common air end problems to aid in troubleshooting.
Decreased Performance
If the volume of generated compressed air (in CFM) begins to drop, the air end is likely losing efficiency. Common causes could be damaged bearings, worn rotors, and seal problems.
Higher Energy Consumption
Air ends transform mechanical energy into pneumatic power. A sign of decreased energy efficiency is if the compressor is consuming more electricity to produce the same amount of compressed air. This could be due to motor issues or wear and tear within the air end, as more power is required to compensate for the higher internal resistance.
Excessive Vibration and/or Noise
Unusual vibrations or noises, such as a growling sound, could be due to damaged or misaligned rotors, worn bearings, or seal problems. These conditions should be addressed promptly, as they can lead to more serious issues.
Higher Operating Temperatures
Oil-lubricated air compressors with correctly functioning air ends should be able to efficiently manage the heat generated from the air compression process. Your compressor’s specification sheet shows what an acceptable temperature rise would be—the typical range is 25 °F to 35 °F higher.
If your compressor is operating higher than this range, it could be a sign of cooling issues, insufficient lubrication, or greater friction from worn parts. Also look for heat marks on the side of the air end. High temperatures can break down the oil and reduce oil life. All of these are potential indications of a failing air end.
Greater Oil Consumption or Leakage
For oil-lubricated compressors, the oil acts as a lubricant, sealant, and coolant. Increased wear or damaged seals in the air end can cause higher oil consumption. If there is oil leakage, there might be a crack in the air end housing or a seal failure.
Water or Metal Particles in the Oil
When bearings, rotors, or other components experience severe wear, they may start to shed metal particles. Identify these particles in the oil sump or oil filter by taking a sample. Water in the oil can cause the oil to be acidic. These are signs of a severe problem that must be addressed through proper inspection and repair.
Pressure Loss
If the seals or rotors are damaged, the air compressor will struggle to produce the right pressure level, causing a significant drop in pressure output. Pressure loss may also be a symptom of other problems in the compressor, so a full diagnostic should be conducted.
Short Cycling
A short cycling air compressor could be improperly sized or have an incorrect pressure setting. If not corrected with the help of an air study, prolonged short cycling can cause air end failure.
Causes of Air End Failure
Below are the main causes of premature air end failure in oil-lubricated rotary vane and rotary screw air compressors.
Insufficient Lubrication
In rotary screw compressors, oil serves as lubrication, sealant, and coolant. These types of inadequate lubrication can result in excessive heat generation, wear, and air end failure:
- Incorrect oil quality or type
- Low oil level
- Oil change intervals not followed
Contamination
Dirt, dust, and other contaminants can get into the compressor with the oil or through the air intake, causing accelerated wear on the bearings and rotors. Thus, facilities must maintain good oil and air filtration.
Overheating
Overheating can break down the oil, causing sludge and varnish buildup. High operating temperatures may also damage sealing components and other parts. Overheating is a result of high ambient temperatures, inadequate cooling systems, or excessive load.
Poor Maintenance
Poor maintenance is a common cause of air end failure. Proper maintenance comprises regular replacements of air filters, oil sampling, oil changes, and checks of rotors, seals, and bearings for signs of wear.
Operating Beyond Parameters
Operating a compressor beyond its specified capabilities—such as duty cycle, temperature, or pressure—can strain the air end and cause premature failure. Also check the compressor’s run hours, as most air end bearings are rated for about 50,000 hours and may need proactive replacement.
Imbalance or Misalignment
Air end rotors must be properly aligned and balanced for smooth operation. Bearing wear, improper rotor installation, and rotor or casing damage can cause the misalignment or imbalance. If left unaddressed, the excess wear and vibration can cause the air end to fail.
Air Compressor Air End Rebuilds From John Bouchard & Sons
If your compressor air end is experiencing any of the issues discussed, rebuilding it is often the most economical way to maximize your investment at a fraction of the cost of a new machine.
John Bouchard & Sons (JBS) specializes in supplying, repairing, rebuilding, and installing compressed air equipment. JBS IN-HOUSE air end rebuilds are much less expensive than factory-exchanged rebuilt air ends. We provide 24/7 technical service to help you troubleshoot your unique air compressor issues and minimize system downtime. With locations in Tennessee, Kentucky, and Indiana, John Bouchard & Sons is an experienced service provider for all major compressor brands, including Gardner Denver, Ingersoll-Rand, Atlas Copco, Sullair, Quincy, Kaeser and many other major compressor manufacturers.
Learn more about our Compressed Air Solutions here. They include:
- Air End Rebuilds
- Service & Repair
- Equipment rentals
- Replacement parts
- New equipment purchasing
Contact us to get started on your industrial air compressor solution.
