Last Updated: September 12, 2026
[geo_answer label=”Quick Answer”]Written by Penny Winston, Blog Writer, AirSpace Machinery Co., Ltd. — a 4,000 m² compressor manufacturing facility in Shanghai, ISO 9001:2015 certified and CE marked.
Reviewed by Richard Moore, Field Technical Manager.
This comprehensive guide explains how to properly maintain oil-free air compressors (OFACs) to maximize their operational lifespan and ensure consistent performance. Whether you are a facility manager, maintenance technician, or industrial equipment operator, the step-by-step maintenance procedures outlined below will help you protect your investment and avoid costly downtime.
My customers usually would ask a few questions about Air Compressors, and the most FAQ was “The best way to maintain an oil-free compressor”. As a supporting facility, Oil-free air compressors(OFAC) need to be checked and maintained regularly after a period of time, in the overall process from start-up to operation, to prepare materials and consumable parts to help extend the lifespan of those machines.
Before that, follow the normal shutdown procedure to simply reduce the speed gradually to a very low level. Then switch on the discharge valve completely to close the discharge door, switch off the motor and wait for the entire compressor to stop. Please take note that the cooling water supply should remain working for the next 30 minutes after the shutdown.
According to the Compressed Air and Gas Institute (CAGI), proper shutdown and maintenance procedures can extend compressor service life by up to 30% while reducing unexpected failure rates by as much as 50%.
Secondly, after completing the operation of the OFACs, check the various levels of cutting edges as well as the fits between the cut pieces and the cutting object. Replace the cracked ones with new spare parts on the cutting pieces, if applicable. Take a closer look at the front cover of the cylinders at each level and see the attrition rate on the mirror surface. In case of signs, find out why. Examine the abrasion of the cross slide and the friction surface with the body guide. Remove the connecting rod head bushings and crosshead pins to check the friction surfaces.
Likewise, it is essential to check the oil level on the indicator to make sure it meets the minimum requirements. Manually hand-pull all the fixings and connections on the machine, and fix them back promptly if there is any looseness. Observe and judge whether all the movable parts can flexibly move. Turn the flywheel 2-3 times by hand to find out any jams and collisions.
Finally, look over the quality of the OFAC’s lubricant and replace them timely. In a normal case, a large number of fine metal specks of dust would enter the lubricant after the initial operation, due to the wearing and tearing, and the cleaning effect of the lubricant. Therefore, all lubricants should be replaced after 24 hours of initial operation, and then change the oil after 200 hours of again. Afterward, do regular changes in accordance with maintenance requirements.
Air coming to the compressor should be clean; although some tiny (around 1 micron or less) particles might enter. However, a very low quantity of tiny particles might not be harmful to the compressors.
I hope this helps! Let me know if you have any other questions.
Frequently Asked Questions About Oil-Free Air Compressor Maintenance
How often should I replace the lubricant in an oil-free air compressor?
For oil-free air compressors, lubricants should be replaced after the first 24 hours of initial operation, then again after 200 hours of use. After this break-in period, follow the manufacturer’s recommended maintenance schedule for regular oil changes to ensure optimal performance and longevity.
Why is it important to keep the cooling water running after shutdown?
The cooling water supply should remain active for approximately 30 minutes after shutdown to allow the compressor components to cool down gradually. This prevents thermal shock and reduces stress on internal parts, which helps extend the overall service life of the equipment.
What should I inspect on the cylinder surfaces during maintenance?
During maintenance, carefully examine the front cover of the cylinders at each level and assess the attrition rate on the mirror surface. If you notice any signs of unusual wear or damage, investigate the root cause immediately to prevent further deterioration and potential equipment failure.
How can I tell if my oil-free compressor has loose connections?
Manually hand-pull all fixings and connections on the machine during your regular maintenance inspection. Any components that feel loose or move unexpectedly should be tightened promptly. Additionally, turn the flywheel 2-3 times by hand to detect any jams or collisions that may indicate loosening parts.
What size particles can safely enter an oil-free air compressor?
Air entering the compressor should ideally be clean, though particles around 1 micron or smaller may occasionally pass through. A very low quantity of these tiny particles is generally not harmful to the compressor, but maintaining clean intake air remains important for optimal performance and longevity.
How do I properly shut down an oil-free air compressor?
Follow the normal shutdown procedure by gradually reducing speed to a very low level first. Then fully open the discharge valve to close the discharge door, switch off the motor, and wait for the compressor to stop completely. Remember to keep the cooling water running for 30 minutes after shutdown.
What causes metal particles to appear in compressor lubricant?
Fine metal specks typically enter the lubricant after initial operation due to normal wearing and tearing of internal components, combined with the cleaning effect of the lubricant itself. This is why replacing all lubricants after 24 hours of initial operation is essential, followed by another change after 200 hours of use.
Key takeaways
- This is why replacing all lubricants after 24 hours of initial operation is essential, followed by another change after 200 hours of use.
- Therefore, all lubricants should be replaced after 24 hours of initial operation, and then change the oil after 200 hours of again.
- Following a structured maintenance schedule—replacing lubricants after 24 hours of initial operation and again after 200 hours—significantly extends the service life of these machines.[/geo_answer].
⚡ Is Your Factory Bleeding Cash?
Most fixed-speed compressors waste $3,600/year in "Unload Tax." Test your waste level in 30 seconds.
RUN THE ROI TEST →Ready to See How Much Your Facility Can Save?
Fill out the form below for a Free Energy Assessment.
