1. the compressor oil runs out of viscosity without replacement, it will  stick on oil separator  and heat separator due to oxidation.
2. Periodically replace lubricants and oil separator according to maintenance standards. Dirty oil may cause the oil separator  burnt.
3. Check the lubricanting level with the oil level gauge on the oil case  when the machine is operating (loading operation). Normally if it is between 2 red lines
-  when it's over the upper  red line showing excessive oil. Stop the air compressor and then check if there is any residual pressure remaining inside, discharge excess pressure with the draining  valve on the oil case  etc.

- If the oil level is leser than lower red lines. Stop the air compressor then check the residual pressure, replenish lubricants. Periodically replenish lubricating oil to maintain the stable oil level. Long time operation without oil replenishment may shorten the using time and damaged oil.

- The time for oil replenishment may carry out from 1500-2000 hours operating time( total oil replenishment is determined by oil level, it can change depending on loading rate of air compressor).

- Oil analysis  had better be caried out for every 3000 operating  hours, the oil change is up to the analyzied result.