Oil Filter
The oil filter element of the new screw air compressor should be replaced after 600 hours’ operation. When replacing the oil filter element, please carefully wipe the dirt and oil while preventing contaminants from entering the lubrication system. It will alarm when the filter pressure is over 1.7 bar/25psi under the normal operating temperature, which also indicates that the oil filter element should be replaced.

Air Oil Separator
The air oil separator element has integral structure. It can gather the oil mist on its surface and condensed them into mist droplets. The mist droplets will be dropped down to the bottom of separator and recycled back into the compression chamber via the oil return pipe.

The air oil separator must be handled with care to avoid damage. Once the separator element suffers impact, deformation or even a little indentation, the separation efficiency will be affected. Consequently, the screw air compressor will generate air with too much oil, for even a tiny hole on the separator element will result in much oil content.

Under normal circumstances, if the air filter and oil filter are properly maintained, the air oil separator does not need periodic replacement. However, if the following situations occur, the air oil separator element should be replaced:
1. The differential pressure is over 1.0kg in the action of separator pressure switch;
2. The compressed air still contains too much oil even when the oil level, load, unload and oil return system have been determined to be normal.

Air Filter
1. The dust bag, dust cover and intake silencer should be cleaned everyday. Frequent cleaning is required in dusty environment. The screw air compressor is recommended to be placed in outdoor environment with clean air supply.
2. When the air filter’s vacuum switch acts, the pressure loss reaches 25 " of the water column and the indicator lights, the air filter element should have maintenance.
3. The air filter and the air inlet system’s sealing performance should be checked every 500 working hours or three months.
4. Under normal conditions of use, the air filter element should be replaced every 2,000 working hours or 1 year.
5. If in adverse and dusty environment of ceramic and cement, the air filter should have frequent maintenance and shorter replacement period.
6. When it comes to replace the overloaded filter, the security element should also be replaced, though the security element doe not need maintenance during the use.
7. Please ensure the downstream side of the filter element is clean, which can guarantee the absolutely reliable air tightness between the air filter’s connection with the compressor’s sealing elements, such as threaded connection, flanged connection and leather hose.

Safety Valve
The safety valve should be kept clean to guarantee its open and self-closing function. If the safety valve failed to open, it could not protect the pressure system and leave the screw compressor unsecured.

If the safety valve loses the self-closing function, the lubricants in the air oil separator will massively eject and result in property loss. Therefore, we should stop the air compressor and check the status of the safety valve every week.

Secondary Oil Return Line
The secondary oil return line can direct the accumulated oil inside the air oil separator element back to the low pressure chamber of screw compressor. Its oil return orifice is used to ensure the stability of oil return.

If the secondary oil return line has severe blockage mainly in the orifice and filter, the compressed air will have too much oil content. Therefore, the secondary oil return line should be checked regularly. If equipped, the orifice and filter should be cleaned.

In routine maintenance, if you can not see the lubricant flowing back to the observation window or the compressed air contains too much oil, the orifice should be cleaned. Also, the lubricant should be changed every six months.