Loading and unloading are fundamental functions of a compressor. If it cannot load or unload, the compressor is useless. If it cannot load, there will be no compressed air output; if it cannot unload, when there is no demand for compressed air downstream, the consequence can be imagined as "continuously inflating a balloon." During operation, when the rated pressure exceeds the set pressure, the compressor will continue to operate under load, leading to the screw compressor tripping and shutting down, or the safety valve activating when the maximum pressure value is reached.
If there is no situation where the actual production air consumption is greater than the compressor unit's air output and there are no significant leaks in the pipeline, the reasons why the compressor cannot unload are as follows:
1. The pressure switch is incorrectly set or fluctuates after setting, resulting in erroneous readings;
2. The intake valve is not operating smoothly or is stuck;
3. When the system stops using air, the overflow solenoid valve malfunctions, resulting in a slow pressure increase instead of immediate unloading;
4. Control circuit failure;
5. Loading solenoid valve malfunction, such as loading and unloading simultaneously, where the amount of loaded gas is greater than the unloaded amount, so the pressure continues to rise.
For compressor failures where unloading is not possible, check whether various valves are stuck or damaged, and repair or replace them if necessary.
Currently, screw compressor manufacturers perform standardized factory settings before shipment. Most problems are caused by untimely maintenance or improper operation. If we strictly follow the machine operating procedures and pay attention to equipment maintenance, many unnecessary equipment failures can be avoided.