When a screw air compressor fails to unload properly, it can lead to inefficient operation, excessive pressure build-up, and even triggering of the safety valve. Below, we explore common causes for this issue and provide targeted troubleshooting solutions.
 

Signs of a Faulty Air Compressor Unloading Process

The primary symptom of an unloading issue is when the compressor continues to operate beyond the set pressure without unloading or experiences a rise in pressure until the safety valve is activated. Identifying the exact cause requires a systematic approach to inspection and diagnosis.
 

Possible Causes and Solutions

 

Improperly Set or Faulty Pressure Switch

Cause: If the pressure switch is not set correctly or has drifted from its original setting, the compressor may fail to respond appropriately to pressure changes. This issue may also arise from a controller failure.
Solution: Inspect the pressure switch settings, recalibrate if necessary, and check the controller for potential faults. Replace the pressure switch if recalibration does not resolve the issue.

 

Intake Valve Malfunction

Cause: A poorly functioning intake valve can prevent the compressor from unloading properly by failing to close or open completely.
Solution: Examine the intake valve for any mechanical faults, debris, or blockages that might be restricting its movement. Clean, lubricate, or replace the intake valve if needed to restore its proper function.

 

Drainage Solenoid Valve Failure

Cause: When the system stops using gas, a malfunctioning drainage solenoid valve may result in a gradual pressure build-up due to improper pressure relief.
Solution: Check the solenoid valve for electrical and mechanical failures. Clean or replace the solenoid valve if it is not functioning as intended.

 

Control Loop Failure

Cause: A fault in the control loop can disrupt the unloading process, preventing the compressor from reducing pressure as expected.
Solution: Inspect the control circuit for wiring issues, component failures, or loose connections. Repair any damaged connections or replace faulty components within the control loop.

 

Troubleshooting Approach

To address these issues effectively:
 

• Conduct a systematic inspection of each potential fault area.
• Clean, adjust, and recalibrate components as necessary.
• Replace malfunctioning parts to ensure reliable and efficient unloading of the air compressor.

By following these troubleshooting steps, you can identify and resolve the issues preventing proper unloading in screw air compressors, optimizing performance and enhancing the safety of the equipment.