1.The unloading pressure set value the is too low.  

Set the pressure value correctly and  give full play to the efficiency.

2.The paraffin of the filter is dirty or have a block. This will result in the insufficient air inflow of the air compressor’s units and the too-low discharge pressure. 

Check the filter and change it if necessary.

3.The solenoid valve has a failure.

If necessary, change it.

4.The tube of the control gas path has a leakage. 

Change it.

5.The intake valve doesn’t respond rapidly and the intake valve do not open completely. 

You need check and maintain the condition of the control system.

6.The oil air separator have a block,

Change it.

7.The safety valve has a leakage. 

You need re-calibrate it or change the valve.

8.The drain valve of the gas-water separator get stuck during the open time and this result in the leakage.

Maintain it.

9.The venting valve has a failure and the units can not close during the loading.

Maintain it or change it.