The air compressor is the "heart" of many manufacturing operations, providing the essential compressed air energy source. However, continuous operation in harsh environments often leads to wear and tear and performance degradation. Implementing a Periodic Preventive Maintenance Checklist is a key strategy to ensure stable system operation, extend equipment lifespan, and avoid costly, sudden breakdown repairs. Below are the necessary inspection items for a typical screw air compressor system.

1. Daily Check List

These quick checks should be performed by the operator before or after each shift to detect problems early.

• Check Oil Level: Ensure the oil level is within the safe range on the sight glass.
• Observe Sound and Vibration: Note any strange noises, knocking sounds, or unusual vibrations from the air compressor and motor.
• Check Operating Temperature: Monitor the Air End temperature gauge to ensure it does not exceed the safe limit (95°C to 105°C).
• Drain Condensate: Manually operate the drain valve (or check the automatic valve) on the air receiver tank and air dryer to ensure water is completely discharged.
• Check Discharge Pressure: Ensure the operating pressure is stable and not dropping unexpectedly.

2. Operational Cycle Maintenance List (PM Checklist)

These items must be performed based on the equipment's total Running Hours, following the recommendations of the Original Equipment Manufacturer (OEM).

2.1. 2,000-Hour Cycle (Approx. 3-6 months)

2.2. 4,000-Hour Cycle (Approx. 6-12 months)

Perform all items from the 2,000-hour cycle, plus:

• Replace Compressor Oil: Replace with new Synthetic Oil, removing old oil that has degraded its lubricating and cooling properties (refer to The Importance of Adhering to the Oil Change Cycle).
• Check Drive System: Check the Alignment between the motor and air end (for direct-coupled machines). Replace the Drive Belt if there are signs of cracks or wear.
• Clean Cooler: Clean the exterior of the Oil and Air Cooler to ensure heat dissipation efficiency, preventing overheating.

2.3. 8,000-Hour Cycle (Approx. 12-18 months)

Perform all above items, plus:

• Replace Separator Filter: This is a costly but mandatory item. An old separator filter will cause increased Differential Pressure, raising electricity costs and potentially rupturing, leading to severe oil contamination in the air line.
• Overhaul Inlet Valve and Minimum Pressure Valve (MPV): Inspect and replace the internal gaskets and seals of the control valves to ensure Load/Unload function and maintain minimum pressure.
• Oil Analysis: Take a sample of the used oil to analyze metal wear, viscosity, and contaminant content, helping to predict the lifespan of the Air End.

---

3. Maintenance of the Compressed Air Treatment System

The air compressor is not the only equipment that requires maintenance. The downstream air treatment equipment also needs attention.

• Air Dryer: Replace the Pre/After Filters periodically (usually 6,000 - 8,000 hours). For Desiccant Air Dryers, the adsorbent material (Desiccant) must be inspected and replaced on a strict schedule.
• Automatic Drain Valve: Disassemble and clean the Automatic Drain Valve (e.g., Electronic Drain Valve) to ensure it is not clogged by sludge, preventing water accumulation in the system.

Conclusion

Periodic maintenance is not an expense but a mandatory investment to protect your company's assets. Adhering to the Preventive Maintenance Checklist based on running hours will help the air compressor maintain maximum energy efficiency, minimize the risk of Unplanned Downtime, and extend the lifespan of the Air End (the most expensive component of the compressor). Always use Genuine Spare Parts or High-Quality Equivalent Parts to ensure the system operates according to design specifications.

Quoc Thinh Industrial provides comprehensive Preventive Maintenance services for compressed air systems, helping to build and execute the optimal inspection checklist for your factory.