Answer: The pressure relief pipe of the inlet valve servo cylinder of some air compressors is connected to the pressure relief valve. After the air compressor no-load signal is issued, the pressure relief valve opens and removes the residual pressure of the working air source of the servo cylinder; if the pressure relief valve cannot be opened and closed due to jamming, the pressure relief valve removes the working air source pressure of the servo cylinder when the air compressor needs to be loaded, so that the inlet valve servo cylinder cannot be opened.
To judge this fault phenomenon, just remove the air supply pipe of the servo cylinder. If the air source pressure is normal, it may be that the pressure relief valve removes the working air source pressure of the servo cylinder. At this time, remove the pressure relief pipe connecting the inlet valve servo cylinder and the pressure relief valve, and block it with your hand, and you will find that the servo cylinder is working normally.