8 Common Air Compressor Issues and How to Troubleshoot Them Effectively

Air compressors are vital to industrial operations, and when a failure occurs, it can disrupt entire production lines. Understanding common issues and knowing how to diagnose them quickly is crucial for minimizing downtime and maintenance costs.

As a screw air compressor specialist, I’ve compiled a list of eight frequent problems encountered in air compressor systems, along with clear troubleshooting steps to resolve them.

1. The Air Compressor Fails to Start

Possible Causes:

• No control voltage

• Blown fuse

• Faulty control relay or time relay

Troubleshooting:
Start by checking whether the control circuit receives voltage. If not, inspect the fuse for continuity. If voltage is present, examine whether the control relay and time relay are operating normally. Faulty relays can disrupt the startup sequence.

2. The Air Compressor Fails to Start Smoothly

Symptoms:
The compressor stops automatically after running for only a few seconds.

Troubleshooting:

• Check if the automatic circuit breaker has tripped.

• Verify that the power supply voltage is stable and within the correct range.

• Inspect the intake butterfly valve to ensure it is fully closed during startup (compressors should not start under load).

• If using Y-Δ (star-delta) starting, confirm proper functioning of the contactor and ensure all three motor phases are balanced.

3. The Compressor Does Not Supply Air

Troubleshooting Steps:

• Check if the loading control cylinder is actuating.

• If movement is observed, inspect the butterfly valve for mechanical issues.

• Test whether the ISV solenoid valve coil has proper suction. If not, confirm the coil is intact and receiving voltage.

• If mechanical and coil issues are ruled out, systematically check the control circuit that powers the ISV solenoid.

4. Low Exhaust Pressure

Possible Issues:

• Internal or external air leakage

• Malfunctioning valves or regulators

Checklist:

• Compare pressure readings before and after the oil/air separator.

• Inspect manual valves and 2SV solenoid valves for leakage.

• Check all air pipelines for possible air leaks.

• Ensure the intake butterfly valve is fully open.

• Test if the air intake regulator is responsive and accurate.

• Evaluate solenoid valves 3SV and 8SV for internal leakage.

• Recalibrate or replace the pressure switch (IPS) if it’s not triggering correctly.

5. Compressor Stops Due to Oil Injection

Root Cause:
Oil is being discharged with air, often due to a malfunctioning oil cutoff valve.

Action Steps:

• Test the 5SV oil cutoff solenoid valve for electrical signal and mechanical function.

• If functioning correctly, inspect the check valve. If worn or damaged, reassemble or replace it.

6. Excessive Exhaust Temperature

Normal exhaust temperatures range between 80°C and 95°C. Higher values often indicate inadequate cooling.

Diagnostics:

• Check ambient temperature and ventilation.

• Ensure the lubricating oil level and quality are adequate.

• Confirm cooling fan operation.

• Inspect the oil cooler and aftercooler for blockages.

• Test the temperature control valve and oil stop valve for correct operation. A stuck diaphragm or a faulty valve core must be replaced.

• If oil filters are dirty, clean or replace them to restore oil flow.

7. High Oil Consumption

Abnormal oil usage can result in environmental issues, higher operating costs, and system contamination.

Things to Check:

• Oil levels—make sure they are not overfilled.

• Is the condensate discharge unusually oily? This could indicate poor oil separation.

• Verify the opening pressure of the minimum pressure valve.

• Ensure the return oil line is not clogged.

• Check for a blocked oil separator element, which can drastically increase oil consumption.

8. Automatic Shutdown During Operation

Sudden shutdowns can point to electrical or mechanical protection mechanisms triggering.

Checklist:

• Examine if the shutdown is part of a normal protection routine (e.g., overload or thermal shutdown).

• Check the circuit breaker and thermal relay.

• Determine if the cooling fan motor is still operational.

• Verify if the shutdown was triggered by high exhaust temperature, excessive system pressure, or another alarm condition.

Conclusion

Each of the above issues can significantly affect the performance and safety of your air compressor. By systematically analyzing electrical inputs, mechanical actuators, temperature controls, and system pressures, most problems can be diagnosed and resolved without needing extensive downtime.

Proper maintenance, regular inspections, and understanding your air compressor’s control logic are essential to prevent recurrence. If you’re unsure or if the issue persists, consult with a certified technician or your compressor’s service provider for a professional diagnosis.