Troubleshooting an Industrial Air Compressor: Common Problems and Solutions

Commercial air compressor not working? Our air compressor troubleshooting guide will help you get to the bottom of common air compressor problems and solutions. 

If you’re dealing with a broken air compressor, a pressure problem, or other air compressor problems, the compressed air experts at Fluid-Aire Dynamics can help. We can help with air compressor fault diagnosis, troubleshooting, and air compressor repair services.

Aire Tip: Before working on your air compressor, be sure to fully disconnect it from its power source and follow proper lockout/tagout procedures. Follow all safety precautions in your user’s guide and contact a professional if you do not have the appropriate expertise on staff.

1. Compressor Oil Is Leaking or Does Not Last Long

Proper lubrication is absolutely essential for an oil-flooded rotary screw compressor or reciprocating air compressor. If oil levels are too low, you have the wrong oil viscosity or the oil sump runs dry, you will quickly be faced with a damaged air compressor. Running without oil will damage the air end and lead to costly repairs. 

An oil leak may show up as an obvious pool underneath the compressor, or you may simply notice that oil doesn’t last as long as it should. This is most commonly due to:

• Worn Seals and Gaskets: Heat, pressure, and vibration cause seals and gaskets to degrade over time, leading to oil leakage. In piston compressors, inverted piston rings (incorrect installation) can also cause oil leaks. 
• Damaged Oil Lines or Reservoirs: Cracks, punctures or corrosion in oil lines or reservoirs result in leaks, often caused by aging components or physical damage.
• Loose Fittings or Connectors: Vibration during operation can loosen fittings and connectors, creating gaps that allow oil to escape.
• Faulty Oil Filters: Damaged or clogged oil filters can cause leaks or improper oil flow, compromising lubrication and increasing wear.
• Overfilling the Oil Sump: Too much oil creates pressure that forces oil through seals or vents and increases the risk of contamination in the air system.

What you can do: 

• Inspect Seals, Gaskets, and Connections: Check all seals, gaskets, fittings, connectors, and oil lines for signs of wear, cracks, or damage. Replace any worn, faulty or loose components to prevent leaks and ensure proper oil circulation.
• Change the Oil and Filter: Replace the oil and install a new oil filter to remove contaminants and maintain proper lubrication. Regular oil changes extend the life of your compressor and prevent damage to internal components.
• Avoid Overfilling the Oil Sump: Always follow the manufacturer’s guidelines for oil changes and fill levels. Overfilling with too much oil can cause excessive oil carryover.

Table: Tips for Maintaining Oil Levels and Quality
1. Check Oil Levels Regularly	Inspect the oil level daily or before each use and ensure it stays within the recommended range on the sight glass or dipstick.
2. Use the Correct Oil	Always use the manufacturer-recommended oil type to avoid compatibility or performance issues.
3. Replace Oil on Schedule	Follow the manufacturer’s guidelines for oil change intervals, typically every 500-2,000 hours, depending on the compressor type and usage.
4. Monitor Oil Quality	Look for signs of contamination, such as discoloration, a burnt smell or particulate buildup, and replace the oil if needed.
5. Keep the Sump Clean	Drain and clean the oil sump during oil changes to remove sludge or debris.
6. Inspect for Leaks	Regularly check seals, gaskets and the oil fill cap for leaks that can lower oil levels or contaminate the system.

2. Air Compressor Is Overheating

Air compressor overheating can lead to system failure, reduced efficiency, and costly repairs. This issue is caused by several factors, including:

• Inadequate Lubrication: Insufficient or degraded oil can increase friction and heat generation in moving parts.
• Poor Ventilation: Without proper airflow, heat from the compressor accumulates in the room, causing system components to overheat.
• High Ambient Temperatures: Operating the compressor in a hot environment can overwhelm its cooling system.
• Clogged Filters or Hoses: Obstructions in filters or hoses restrict airflow, forcing the compressor to work harder and generate more heat.
• Problems with the Air Compressor Cooling System: Malfunctioning fans, dirty cooling fins, or low coolant levels in liquid-cooled systems reduce the ability to dissipate heat.
• Over-Cycling (Exceeding the Recommended Duty Cycle): Compressors that run too frequently without sufficient rest periods can overheat, particularly in systems not designed for continuous operation.

What you can do: 

• Follow the Recommended Duty Cycle: Operate within the manufacturer’s specified duty cycle to prevent excessive heat buildup. Ensure proper rest intervals between cycles.
• Maintain the Oil System: Regularly check oil levels and quality. Add oil if low, and replace it if dirty or degraded to ensure proper lubrication.
• Clean or Replace Filters and Hoses: Remove blockages and replace dirty intake and inline filters to maintain proper airflow.
• Optimize Ventilation and Cooling: Ensure the compressor room is well-ventilated. Add fans or cooling systems if needed.
• Inspect the Cooling System: For air-cooled systems, clean fins and ensure fans are working. For liquid-cooled systems, check coolant levels and fix leaks or blockages.
• Monitor Ambient Temperatures: Keep the compressor room within recommended temperature ranges and address persistent heat issues with improved ventilation or cooling solutions.

3. Air Compressor Is Too Loud

Excess noise in an air compressor is often an early indicator of a developing problem. While commercial air compressors can be pretty noisy naturally, if you notice new noises or a change in noise levels, it’s wise to check it out. Common causes of excess noise include:

• Loose, Worn, or Misaligned Parts: Bolts, belts, pulleys, and other internal mechanisms can loosen or wear out over time, creating rattling, clanking, or squealing noises.
• Improper Mounting: A poorly mounted compressor may move excessively or vibrate against surfaces, amplifying noise levels.
• Poor Lubrication: Insufficient lubrication leads to friction between moving parts, often causing squealing, screeching, or grinding noises.
• Misaligned Screws or Damaged Pistons: In rotary screw compressors, misaligned screws can create a high-pitched whine or grinding sound, while damaged pistons in reciprocating compressors can result in knocking or clanking noises.
• Bad Motor Bearings: Worn or improperly lubricated motor bearings often produce whining or grinding sounds and can lead to motor failure if left unaddressed.

What you can do: 

• Inspect Motor Bearings: Check for wear and ensure they are properly lubricated. Replace bearings if damaged. In rotary screw compressors, bearing replacement should be handled by a professional.
• Check and Tighten Parts: Inspect bolts, belts, pulleys, the belt guard and other components. Tighten loose parts and replace any that are worn or damaged to prevent further noise and vibration.
• Ensure Proper Mounting: Verify that the compressor is securely mounted and mounting bolts are secure. Use a rubber mat or vibration pads.
• Maintain Proper Lubrication: Ensure the compressor is properly lubricated with the recommended oil to prevent friction. Check that rotary screws or pistons are moving freely.
• Address Misalignment Issues: If there is evidence of misaligned screws in a rotary screw compressor or piston problems in a reciprocating compressor, consult a professional. Misalignment in the air end may require a rebuild or realignment to restore proper operation.

4. Air Compressor Keeps Blowing Fuses

Repeatedly blown fuses in your air compressor may indicate an underlying electrical problem. Some potential causes include:

• Overloaded Circuits: Sharing a circuit with other high power-consuming devices can cause the circuit to overload, especially if the compressor and other equipment exceed the circuit’s amperage rating. This is a common issue in facilities with multiple heavy-duty machines on the same line.
• Faulty or Worn-Out Motor: A failing motor draws more current than normal, leading to overloading of the circuit and fuse failure.
• Electrical Wiring Issues: Damaged wires or loose connections within the compressor can create electrical shorts or resistance, increasing the likelihood of fuse failure.
• Compressor Overheating: Excess heat can strain the motor and electrical system, causing the compressor to overdraw current.
• Running the Compressor Over Its Rated PSI: Operating the compressor beyond its design limits forces the motor to work harder, increasing power consumption and risking electrical issues.

What you can do:

• Use a Dedicated Circuit: Ensure your air compressor is on a dedicated circuit rated for its amperage to avoid overloads caused by sharing the circuit with other equipment. This prevents excessive current draw.
• Inspect and Maintain the Motor: Check for signs of wear or damage and replace the motor if it is drawing excess current. Use a multimeter to test motor amperage against the manufacturer’s specifications.
• Repair Damaged Wiring: Inspect wires and connections within the compressor for damage or looseness. Replace any damaged wires and secure loose connections to eliminate electrical shorts.
• Optimize Cooling and Ventilation: Operate the compressor in a cool, well-ventilated area to prevent overheating. Regularly clean and maintain the cooling system to ensure proper airflow.
• Adhere to PSI Ratings: Avoid running the compressor over its rated PSI to prevent excessive strain on the motor and electrical system.

5. Air Compressor Will Not Start

If your air compressor won’t start, the problem could range from a simple fix to a more complex issue. If the compressor hums but doesn’t start, it likely has power, and the issue may lie in the motor or the air end. Common causes include:

• Failed Capacitors: Start or run capacitors in the motor can fail, preventing it from generating the torque needed to start.
• Damaged Motor Windings: Worn or damaged windings can disrupt the motor’s electrical field, reducing its ability to start or run efficiently.
• Overload Protection Activation: Overheating or overcurrent situations can trip the compressor’s overload protection, shutting it down.
• Check Valve Failure: A faulty tank check valve may allow backflow into the compressor, creating resistance that prevents it from starting.
• Blocked Intake Filters: Obstructions in the intake restrict airflow, making it difficult for the compressor to start.
• Air End Bearings Failure: Seized or worn bearings can create mechanical resistance, preventing the motor from turning the compressor.

If the compressor does not respond at all, possible issues include:

• Power Supply Issues or Blown Fuses: The compressor may not be receiving power due to a tripped breaker, disconnected cord, or blown fuse.
• Faulty Starter: The starter may not be engaging to deliver power to the motor.
• Cut-In Pressure Settings: If the cut-in pressure is set too low, the compressor won’t start when it should.
• Mechanical or Electrical Failure Inside the Motor: Internal motor issues, such as a seized rotor or electrical short, can completely prevent the compressor from starting.
• Bad Start Switch or Control Board: Electrical components responsible for initiating the compressor may have failed.

What you can do: 

• Check Power Connections: Verify that the power cord is properly connected, the power switch is turned on, and the circuit breakers are not tripped. Replace fuses if necessary.
• Adjust Cut-In Pressure Settings: Ensure the cut-in pressure is set appropriately to trigger the compressor to start when needed.
• Inspect the Check Valve and Filters: Confirm the tank check valve is functioning and that intake filters are free from blockages or obstructions.
• Check the Starter and Capacitors: Inspect the starter for faults and test the capacitors using a multimeter. Replace failed components as needed.
• Evaluate the Motor: If there is a humming sound but no startup, the motor may have internal mechanical or electrical issues, such as a seized rotor or damaged windings. Professional diagnostics may be required to repair or replace the motor.
• Call a Professional If Necessary: If these steps don’t resolve the issue, or if you suspect internal motor failure or damage to critical electrical components, it’s best to seek professional help to avoid further damage or safety hazards.

6. Air Compressor Fails to Stop

An air compressor that fails to stop running poses serious safety risks, including the potential for over-pressurizing the system. Over-pressurization can damage the compressor, tank, or connected equipment, and in extreme cases, it may lead to catastrophic tank failure. Addressing the root cause promptly is critical to avoid accidents and ensure proper operation. Potential causes include:

• Faulty Pressure Release Valve: The pressure relief valve is a critical safety component designed to release excess pressure when the tank exceeds safe operating limits. If this inlet is stuck, damaged, or clogged, the compressor may continue running without relieving pressure.
• Defective Power Switch: If the power switch is damaged or malfunctioning, the compressor may not receive the signal to shut off, causing it to run continuously.
• Defective Pressure Switch: The pressure switch monitors the tank’s pressure and signals the compressor to stop when it reaches the cut-off point. A defective switch can fail to recognize that the cut-off pressure has been reached, keeping the compressor running.

What you can do:

• Cut Power Immediately: Turn off the compressor immediately if it doesn’t stop at the cut-off pressure to prevent over-pressurization.
• Inspect and Replace the Pressure Relief Valve: Check for clogs, corrosion, or mechanical damage. Replace the valve if it fails to release excess pressure as intended.
• Test and Replace the Pressure Switch: Use a multimeter to test the switch. If it’s defective, replace it with one that matches your compressor’s specifications.
• Check the Power Switch: Inspect for wear, damage, or loose connections. Replace the switch if it’s not functioning.
• Verify PSI Setting: Ensure the pressure switch cut-off setting is correct and adjust it as needed to prevent over-pressurization.

7. Excessive Power Consumption

Industrial air compressors are major power consumers, and excessive energy use often signals underlying inefficiencies or equipment issues that could signal an air compressor failing. Common causes include:

• Neglecting Maintenance: Skipping tasks like cleaning, lubricating, replacing filters, and draining condensation can reduce efficiency.
• Air Leaks: An air leak in the system forces the compressor to work harder, wasting energy.
• Operating at Excessive Pressure: Running the compressor above the required pressure unnecessarily increases power usage.
• Aging or Failing Motor: Over time, motors lose efficiency or draw excess power due to wear, leading to higher energy costs.

What you can do:

• Maintain Regularly: Change the oil, clean or replace air and oil filters, and repair leaks to maintain optimal performance and reduce energy waste.
• Optimize PSI: Operate the compressor only at the air pressure needed for your applications to minimize power usage.
• Upgrade to Energy-Efficient Equipment: Replace outdated or inefficient compressors and motors with energy-saving models like Variable Speed Drive (VSD) compressors, which adjust motor speed based on demand.
• Schedule an Energy Audit: If power consumption remains high, have a professional assess your system for inefficiencies and recommend targeted improvements.

8. Air Compressor Does Not Generate Enough Pressure

If you’re having a pressure problem, the issue could stem from the compressor itself, the distribution lines, an improperly sized system or incorrect pressure settings. Common causes include:

• Distribution System Issues: If the compressor generates the correct PSI but you don’t have the desired pressure at the point of use, the problem likely lies in the distribution system. Common culprits include an air leak, blocked inline filters, and quick couplers and hoses.
• Air End Problems: Internal compressor issues such as leaks between high- and low-pressure pistons (reciprocating compressors), misaligned rotors (rotary screw compressors), or leaky seals and gaskets can reduce pressure output.
• Blocked Intake Valve or Faulty Discharge Valve: A clogged air filter or malfunctioning discharge valve or inlet valve can restrict airflow and lower air pressure.
• Incorrectly Sized Compressor: If the application demands more air (CFM) than the compressor is rated for, the system will not be able to maintain adequate pressure.
  Note: If you throttle the discharge/service valve to the plant back slowly and you get full amperage on the compressor, the compressor is most likely not the issue. In this case, the compressor is too small or the distribution system is at fault. 

What you can do: 

• Fix Distribution System Issues: Replace blocked inline filters, limit quick couplers and excessive hoses, and perform an air leak study to identify and repair leaks. (Your power company may pay for this.)
• Check PSI Setting: Ensure the pressure regulator is correctly set and working properly; replace it if needed. Use a pressure gauge to monitor pressure at both the compressor outlet and the point of use to identify where pressure drops are occurring.
• Inspect Intake and Discharge Components: Check intake filters and valves for blockages and ensure the discharge valve operates properly and the discharge pipe is not blocked. Replace any faulty parts.
• Properly Size the Compressor: Confirm the compressor can meet the total CFM and particular PSI requirements for your application. Upgrade to a larger unit or add a secondary compressor if needed.
• Call a Professional for Air End Issues: For problems like rotor misalignment or piston leaks, consult a professional to evaluate and repair the air end.

9. Excess Oil in Discharge Air

Oil carryover in discharge air occurs when the oil used for lubricating, cooling, and sealing escapes into the compressed air. This can damage downstream equipment, contaminate processes, and increase maintenance costs. Common causes include:

• Malfunctioning Oil Separator: A faulty or worn-out separator fails to remove oil from the discharge air in screw compressors.
• Overfilled Oil Sump: Excess oil in the sump, caused by overfilling or a system malfunction, can increase oil carryover.
• Blocked Oil Return Line: In screw compressors, a blockage in the oil return line prevents oil from returning to the sump, forcing it into the discharge air.
• Oil Viscosity Issues: Using the wrong viscosity oil or operating in extreme temperatures can lead to oil carryover.

What you can do: 

• Check Oil Levels and Quality: Ensure oil levels are within the recommended range. Drain excess oil, replace degraded oil, and clean or replace filters. Use oil with proper viscosity as recommended by the manufacturer.
• Inspect the Oil Return Line: Look for blockages caused by sludge, rust, or debris. Clean the line thoroughly or replace it if necessary to restore proper oil flow to the sump.
• Test and Replace the Oil Separator: Verify the oil separator is functioning correctly. If it’s worn or defective, replace it to reduce carryover and energy costs.
• Upgrade Inline Filtration: If oil carryover persists, consider installing or upgrading inline filters to capture residual oil droplets in the compressed air.

10. Air Compressor Intake Obstructed

A blocked or obstructed intake can reduce airflow, lower air pressure, increase energy consumption, and lead to overheating. Here’s what might cause it:

• Clogged or Damaged Air Filters: Neglecting to replace the compressor’s air intake filters regularly allows dust and debris to build up, restricting airflow.
• Faulty Inlet Valve: A malfunctioning inlet valve, intake valve or air intake pump prevents the compressor from drawing in air effectively, disrupting performance.

What you can do:

• Replace Air Filters Regularly: Inspect and replace filters on a schedule to prevent blockages and ensure proper airflow.
• Check for Clogs or Damage: Inspect filters frequently for dust, debris, or damage and replace them as needed.
• Repair or Replace Faulty Inlet Valves: If the inlet or intake valve is not functioning or the valve plate (in piston compressors) is damaged, have it rebuilt or replaced to restore proper air intake.

Additional Problems

While regular maintenance can address many common air compressor problems, there are additional issues that may arise with both piston and rotary screw air compressors and in the broader system. 

Air Leaks

Industrial air compressors can develop air leaks that cause them to lose pressure or waste energy. Common causes of air leaks in the compressor air end include:

• Worn piston rings or seals in reciprocating compressors.
• Leaks from fittings, hoses, or manifolds in rotary screw compressors.
• Faulty intake valve or cracked cylinder head or head gasket.

What you can do:

• To locate an air leak, apply liquid soap and water to fittings and connections and look for bubbles. You can also listen for the hiss of air escaping. 
• Tighten any loose connections and replace damaged components like seals, gaskets, or hoses.

Air leaks also frequently pop up in the compressed air distribution system, especially in the “dirty thirty” — the last 30 feet of hoses and connectors. 

What you can do:

• Perform routine inspections of the air system to catch leaks before they escalate.
• Use an ultrasonic leak detector to identify hard-to-find leaks (or contact us for an air leak audit — we can do it for you!).
• Repair leaks in distribution piping promptly and replace worn hoses and connectors. 

Pressure and Flow Problems

Issues with pressure and flow can disrupt industrial operations and reduce productivity. These problems are often caused by:

• Obstructed filters, which restrict airflow and reduce compressor efficiency.
• No air coming from the hose, due to clogged hoses, improper hose connectors, or low tank pressure.
• Air coming in short bursts, often resulting from improper gauge settings, pressure switch malfunctions, or insufficient storage capacity.

What you can do:

• Clean or replace intake air filters regularly to maintain optimal airflow.
• Verify hose connectors are compatible and free of obstructions.
• Check the tank pressure to ensure it meets operational requirements and adjust gauge settings as needed.
• Inspect the pressure switch and storage tank for potential faults, especially in rotary screw systems where oil separator issues may arise.

Oil in Air Lines

Oil contamination in air lines can damage tools and equipment, compromise finished products and disrupt operations. Common causes include:

• Worn or damaged piston seals in reciprocating compressors, leading to oil entering the compressed air.
• Overfilled oil sumps or faulty oil separators in rotary screw compressors, allowing oil carryover into the system.
• Oil/water separator failure, which prevents proper separation of oil from condensate, leading to increased oil contamination downstream.
• Inadequate maintenance of downstream components like coalescing filters, resulting in oil bypassing these safeguards.
• Improperly functioning air dryers, which fail to remove moisture and oil vapor, exacerbating contamination.

What you can do:

• Regularly check and maintain the oil level in the compressor’s sump, ensuring it’s not overfilled and using only the manufacturer-recommended oil type.
• Inspect air lines and downstream equipment for oily residue, discoloration, or buildup, particularly in critical points like inline filters and tools.
• Replace worn seals, repair faulty oil separators, and ensure coalescing filters are cleaned or replaced at recommended intervals.
• Maintain and monitor air dryers and aftercoolers to minimize oil vapor in the system.
• Implement a routine maintenance schedule across the entire system, including inspections of all components prone to oil carryover.

Air Compressor Parts and Repair

Preventive maintenance and timely repairs are essential to addressing common air compressor problems. Air compressor replacement parts include filters, manifolds, compressor fans and cooling systems, on/off switches and gauges. Steps you can take include:

• Inspect and clean or replace intake air filters regularly.
• Tighten or replace manifolds and pipe fittings as needed to prevent leaks.
• Ensure cooling fans are clean and functioning properly to prevent overheating.
• Test on/off switches and gauges for accuracy and replace them when necessary.
• Use high-quality parts and follow the manufacturer’s specifications for replacements.
• Call professionals for repairs involving complex components like the motor, bearings, or control systems.
• Seek professional help for recurring issues like excessive noise, significant air leaks, or oil contamination that regular maintenance cannot resolve.

See our Complete Guide to Industrial Air Compressor Preventative Maintenance for more maintenance tips. 

Common Air Compressor Parts Needing Replacement

Reciprocating Air Compressors	Rotary Screw Air Compressors	Compressed Air System/ Distribution
Intake air filters Oil filters Lubrication system components Piston rings/cylinder liners Inlet and discharge valves Gaskets and seals Crankshaft and bearings Connecting rods Check valve	Intake air filters Oil filters and separators Lubrication system components Control valves Bearings Seals and gaskets Cooling system components (fans, heat exchangers) Motor and drive components	Inline filters Hoses Quick connectors Oil/water separator Condensate drains Pressure regulators Pressure gauge

Need Help Troubleshooting Air Compressor Problems?

Whether your air compressor is not working, is exhibiting unusual behavior, or simply isn’t operating as efficiently as you would like, Fluid-Aire Dynamics can help. We are the experts in commercial air compressor maintenance and repair and compressed air system audits. We also offer 24/7 emergency repair services with a four-hour response guarantee for customers within 90 miles of our service centers in Chicago, Milwaukee, Minneapolis, Detroit and Philadelphia.

Contact us for air compressor service and repair.