Compressors are vital to industrial operations, and when a breakdown occurs, it can disrupt entire production lines. Understanding common issues and knowing how to diagnose them quickly is critical for minimizing production downtime and upkeep expenses.
Key Takeaways
- No control voltage
- Faulty control relay or time relay
- Check if the automatic circuit breaker has tripped.
As a screw compressor specialist, I’ve compiled a list of eight frequent problems encountered in compressor systems, along with clear fault diagnosis steps to resolve them.
The Compressor Fails to Start
Possible Root causes:
- No control voltage
- Blown fuse
- Faulty control relay or time relay
Fault diagnosis: 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.
The Compressor Fails to Start Smoothly
Symptoms: The compressor stops automatically after running for only a few seconds.
Fault diagnosis:
- 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 guarantee 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 guarantee all three motor phases are balanced.
The Compressor Does Not Supply Air
Fault diagnosis 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.
Low Discharge 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.
- Guarantee 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.
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.
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.
- Guarantee the lubricant 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.
High Oil Consumption
Abnormal oil usage can result in environmental issues, higher operating expenses, 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.
- Guarantee the return oil line is not clogged.
- Check for a blocked oil separator element, which can drastically raise oil consumption.
Automatic Power-down During Operation
Sudden shutdowns can point to electrical or mechanical protection mechanisms triggering.
Checklist:
- Examine if the power-down is part of a normal protection routine (e.g., overload or thermal power-down).
- Check the circuit breaker and thermal relay.
- Determine if the cooling fan motor is still operational.
- Verify if the power-down was triggered by high exhaust temperature, excessive system pressure, or another alarm condition.
Conclusion
Each of the above issues can significantly affect the output performance and safety of your compressor. By systematically analyzing electrical inputs, mechanical actuators, temperature controls, and system pressures, most problems can be diagnosed and resolved without needing extensive production downtime.
Proper upkeep, regular inspections, and understanding your compressor’s control logic are essential to avoid 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.
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Frequently Asked Questions
What should I check first when a compressor will not start?
Confirm power supply, control settings, and emergency stop status, then check the pressure switch and any start protection devices.
Why does my compressor run hot?
Common causes are restricted airflow, low oil level, a blocked cooler, or high ambient temperature. Clean the cooler and verify lubrication first.
What does excessive oil consumption mean?
It usually indicates worn separator elements, overfilling, or a leak in the oil circuit. Inspect the separator and seals.
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