Check for correct oil level at the ll plug location on the compressor. The oil level is full when oil is at the bottom of the threads in the ll plug hole. Check for oil purging from the air dryer. Refer to the image below as an example.
[pdf] We specialize in high-efficiency rotary screw air compressors engineered to deliver unmatched reliability, energy savings, and durability for demanding industrial operations.Our oil-free rotary screw technology eliminates contamination risks while reducing maintenance costs, making it the ideal choice for manufacturing, automotive, and heavy machinery applications.
[pdf] Bringing you a prosperous future where energy is clean, abundant, reliable, and affordable 46.3% reduction ($160k/yr!!) in energy usage with the same air compressors, 48.0% reduction in demand, 45.8% improvement in specific power. Wear and tear reduced dramatically. 6.1% pressure reduction.
[pdf] 
