Common Causes of Low Outlet Pressure in Screw Air Compressors and How to Fix Them

When the outlet pressure of a screw air compressor drops below the required level, it can hinder production and lead to inefficiencies. There are various reasons why the outlet pressure may become insufficient, and identifying these causes is essential for maintaining optimal performance. Here, we will explore the common factors behind low outlet pressure and provide solutions to resolve the issue.

1. Excessive Air Consumption or Pipeline Leaks

One of the most common reasons for insufficient outlet pressure is that the compressor is being overworked due to excessive air consumption on-site. In some cases, there may also be air leaks in the pipeline, which further reduce the pressure. It’s recommended to check the entire system for leaks and fix any that are found. Monitoring air usage to ensure it doesn’t exceed the compressor’s capacity can also help maintain stable pressure.

2. Faulty Air Intake Valve

The air intake valve regulates the amount of air entering the compressor. If the valve is faulty or doesn’t open fully, it will result in reduced airflow and lower outlet pressure. In such cases, you should disassemble the valve for inspection and maintenance. If the problem persists, it may be necessary to replace the air intake valve or its repair kit.

3. Air Source Leakage at the Intake Valve

Air source leaks can prevent the air intake valve from opening fully, or in some cases, from opening at all. Any leak in this area will lead to a reduction in pressure. Identifying and fixing the leak is essential to restoring the valve’s proper function.

4. Incorrect Pressure Settings on the Pressure Switch

If the pressure switch of the air compressor is set too low, the compressor will not reach the required outlet pressure. Adjust the upper pressure limit in the pressure switch settings to meet the production demand.

5. Malfunctioning Pressure Switch

A malfunctioning pressure switch can cause incorrect pressure readings, leading to insufficient outlet pressure. To fix this, the pressure switch should be inspected and repaired. If the switch cannot be repaired, replacing it with a new one is recommended.

6. Incorrect Computer Pressure Settings or Faulty Pressure Transmitter

Low outlet pressure can also occur if the computer-controlled pressure settings are incorrect, or if the pressure transmitter is faulty. First, adjust the computer settings and calibrate the pressure transmitter. If the transmitter is defective, replace it to restore normal pressure.

7. Faulty Load Solenoid Valve

The load solenoid valve plays a key role in controlling the compressor’s air source. If the valve is leaking or malfunctioning, it can cause insufficient air supply, leading to low pressure. Remove the solenoid valve for inspection and, if necessary, replace it with a new one.

8. Blocked Air Filter

A clogged air filter restricts airflow and reduces the pressure coming out of the compressor. It’s essential to regularly inspect the air filter and perform maintenance. If the filter is heavily blocked, replacing it is the best solution.

9. Blocked Oil-Gas Separator

The oil-gas separator is another component that can become blocked, leading to pressure drop. If the pressure difference in the separator exceeds 0.8–1 kg, it’s time to replace the separator to avoid further performance issues.

10. Loose Drive Belt

A loose drive belt can significantly reduce the transmission efficiency, affecting the compressor’s performance and outlet pressure. Tightening the belt can solve the issue, but if the belt is damaged, replace it with a new one for optimal operation.

11. Worn Air Intake Valve Coupling

The air intake valve coupling may wear down over time, causing the valve to not open fully. Replacing the worn-out coupling will help restore proper air intake and improve outlet pressure.

12. Reduced Efficiency of the Synchronous Motor

Lastly, a decline in the efficiency of the compressor’s synchronous motor can also result in reduced pressure. If the motor is no longer functioning at its full capacity, replacing it with a new one is necessary to prevent further pressure issues.

Conclusion

Low outlet pressure in screw air compressors can be caused by a variety of factors, from air leaks to mechanical failures. Regular maintenance and timely replacement of worn-out components can help prevent pressure drops and keep the compressor running efficiently. By addressing these common issues, you can ensure optimal performance and minimize downtime in your operations.