Advantages of an 11kW industrial screw air compressor

Industrial screw air compressors, as the “heart” of modern industrial production, directly impact a company’s production efficiency and operating costs through stable and efficient operation. However, in daily use, screw air compressors inevitably encounter various operational malfunctions. The ability to quickly diagnose and effectively resolve these problems is a crucial skill that every equipment manager and technician must master.

This article aims to provide you with a comprehensive guide to diagnosing and troubleshooting common industrial screw air compressor faults, covering a range of common issues from “what to do if the air compressor won’t start” to “solutions for excessively high exhaust temperature in screw air compressors.” It has also been optimized for long-tail keywords such as screw air compressor repair tutorials and air compressor fault code lookups. Bookmark this article, and you’ll be able to easily handle various air compressor problems, ensuring the smooth operation of your production line!

When your screw air compressor fails to start, it usually indicates a problem with the electrical system, motor, or control logic.

Possible Causes and In-Depth Diagnosis:

Power Supply Issues:

• Check for stable power supply voltage: Fluctuations or excessively low voltage can prevent the air compressor from starting properly. Use a multimeter to measure the incoming voltage and ensure it is within the rated range.
• Check Fuses or Circuit Breakers: Blown fuses or tripped circuit breakers are usually caused by overload or short circuit. Check the line load and replace the appropriate fuse or reset the circuit breaker.
• Main Circuit Contactor Failure: Burnt contact points or damaged coils can prevent the contactor from closing. Observe the contactor’s condition and replace it if necessary.
• Power Phase Loss: The loss of any one phase in a three-phase power supply can prevent the motor from starting or trigger overload protection.

Motor and Transmission System Faults:

• Burnt-out or Short-circuited Motor Windings: A burnt smell or abnormal winding insulation resistance measured with a megohmmeter indicates a motor fault.
• Seized or Severely Worn Motor Bearings: Abnormal noise during startup or resistance when turning the motor shaft by hand.
• Damaged or Seized Couplings: Check for wear on the coupling’s elastic element and loose bolts.

Control System Faults:

1. Starter (Star-Delta Starter, Soft Starter, Frequency Converter) Fault: Check for problems in its control circuit and main circuit, such as damaged relays or incorrect parameter settings.
2. Emergency Stop Button Pressed: Check if the emergency stop button has been accidentally pressed.
3. Pressure Sensor or Pressure Switch Fault: When the system pressure signal is abnormal, the control system will prevent the air compressor from starting. Try disconnecting the pressure sensor/switch to see if a simulated start can be achieved.
4. PLC or Controller Program Fault: Complex control systems may have software faults, requiring professional diagnosis.
5. Thermal Relay or Overload Protector Tripping: Prolonged motor overload can cause the thermal relay to trip. Check if the motor operating current is normal.

Loading valve or unloading valve malfunction:

Loading valve not fully unloaded: The air compressor starts under load, causing excessive starting current and triggering a protective shutdown. Check if the unloading solenoid valve is working properly and if the unloading air path is unobstructed.

Solutions and air compressor repair steps:

1. Power off safety check: Before performing any repairs, always disconnect the power supply and display a “Do Not Operate” warning sign.
2. Check electrical components one by one: Following the diagnostic approach above, use a multimeter, clamp meter, and other tools to check the power supply, fuses, contactors, thermal relays, motor windings, etc., one by one.
3. Check control logic: Familiarize yourself with the air compressor’s electrical schematic diagram, check the continuity of the control circuit, and ensure all safety interlock conditions are met.
4. Manually check mechanical parts: Try manually rotating the main unit (without power) to check for any jamming.
5. Seek professional help: For complex electrical or control system faults, it is recommended to contact the air compressor manufacturer’s technical support or a professional repair team.

Insufficient pressure in screw air compressors is a common problem that directly affects production efficiency. This is usually related to mismatches in air intake, leakage, or air demand.

Possible Causes and In-Depth Diagnosis:

Intake System Faults:

Clogged Air Filter: A dirty air filter restricts air intake, leading to a drop in discharge pressure. This is one of the most frequently overlooked problems in routine air compressor maintenance.

Intake Valve Fault or Incomplete Opening: A stuck intake valve (butterfly valve or slide valve) or a damaged solenoid valve results in insufficient air intake.

Air Line Leaks:

Leaks in Piping, Valves, and Joints: Compressed air is lost during delivery. Check using soapy water or a leak detector.

Minimum Pressure Valve Fault: A minimum pressure valve with an excessively low opening pressure setting or poor internal sealing causes some compressed air to enter the oil-gas separator or be discharged without being fully compressed.

Oil-Gas Separator Core Damage or Aging: Damage to the separator core can cause air short-circuiting and a drop in pressure.

Loading/Unloading System Failure:

Poor sealing of the loading or unloading valve: Leads to compressed air backflow or bypass.

Inaccurate pressure sensor or pressure switch: Misjudges system pressure, causing premature unloading.

Degraded Compressor Performance:

Excessive internal clearance in the compressor: Long-term wear and tear reduces compressor efficiency and compression ratio. This is a signal for major overhaul of the screw air compressor.

Screw rotor wear: Affects compression efficiency.

Air consumption exceeds the compressor’s rated supply: New equipment added to the production line or a sudden increase in air consumption leads to insufficient air supply from the compressor.

Solutions and Screw Air Compressor Maintenance:

Replace the air filter regularly: Strictly follow the compressor’s maintenance cycle for replacement to ensure clean and unobstructed airflow.

Inspect and repair the intake valve: Clean the inside of the valve, check the solenoid valve’s operation, and replace if necessary.

Seal leaks: Investigate and repair all potential leaks.

Check the minimum pressure valve: Check its set pressure and replace damaged seals or valves.

Replace the oil-gas separator core: Replace with a high-quality oil-gas separator core regularly.

Adjust the pressure sensor/switch: Calibrate or replace the faulty pressure sensor/switch.

Assess air demand: If actual air consumption is excessive, consider adding a backup air compressor or upgrading existing equipment.

Main unit overhaul: If insufficient pressure persists after ruling out other possibilities, a major overhaul of the screw air compressor main unit may be necessary, replacing worn parts.

Overheating of the air compressor discharge temperature is a common cause of air compressor shutdown protection, and in severe cases, it can lead to compressor head seizure. Understanding the causes is crucial for resolving overheating issues.

Possible Causes and In-Depth Diagnosis:

Inefficient Cooling System:

Radiator (Oil Cooler, Aftercooler) Blockage: Radiator fins are blocked by dust and sludge, reducing the heat dissipation area. This is a common cause of poor air compressor heat dissipation.

Cooling Fan Failure: Damaged fan motor, deformed blades, or reverse rotation result in insufficient airflow.

Cooling Water Flow or Quality Issues (Water-cooled Machines): Failed cooling water pump, blocked pipes, or excessive scale buildup affect heat dissipation.

Lubrication System Issues:

Low Lubricating Oil Level: Insufficient lubricating oil prevents timely removal of frictional heat.

Deteriorated or Ineffective Lubricating Oil: Oxidized lubricating oil or decreased viscosity leads to poor heat dissipation and lubrication performance. This is why strict adherence to air compressor oil change intervals is essential.

Oil filter blockage: Affects lubricating oil circulation, leading to increased oil temperature.

Thermostatic valve malfunction: The thermostatic valve cannot open properly, preventing cooling oil from entering the radiator, causing a short circuit in the oil circuit and a continuous increase in oil temperature.

Environmental factors：

Poor ventilation in the air compressor room: High ambient temperature or the air compressor being too close to the wall affects heat dissipation.

Improper air compressor installation location: Hot air is repeatedly drawn in.

Internal faults in the compressor unit: Excessive internal friction in the compressor unit: Bearing wear, abnormal rotor clearance, resulting in excessive heat generation.

Severe blockage of the oil-air separator core: Increases back pressure in the compressor unit, leading to increased load and higher temperature.

Solutions and air compressor maintenance:

• Clean the radiator: Regularly clean the radiator with compressed air or high-pressure water to ensure proper heat dissipation.
• Check the cooling fan: Ensure the fan is operating normally, with correct airflow direction and sufficient air volume.
• Check the lubricating oil: Check the oil level and replace with lubricating oil and oil filter that meet the manufacturer’s specifications on time. Check the thermostatic valve: Remove the thermostatic valve and test its opening temperature and stroke by placing it in hot water. Replace it if damaged.
• Improve the operating environment: Ensure good ventilation in the air compressor room, lower the ambient temperature, and keep it clean.
• Regularly inspect the main unit: For air compressors that operate at high temperatures for extended periods, it is recommended to inspect the main unit and perform maintenance if necessary.

Industrial screw air compressors experience a variety of malfunctions, but by understanding common faults and their solutions, problems can be identified and addressed promptly, minimizing downtime and ensuring smooth production. It is recommended that companies establish a comprehensive air compressor maintenance plan, regularly inspecting, maintaining, and replacing vulnerable parts to prevent problems and ensure long-term stable and efficient operation of the air compressor.

If you have any questions about air compressor maintenance or encounter any unsolvable malfunctions, it is recommended to contact a professional air compressor repair service provider for expert assistance.