Atlas Copco ZA5 Inlet Valve Kit Replacement – 2906051500

The Atlas Copco 2906051500 is a ZA5 Inlet Valve Kit, used to service and overhaul the inlet-valve assembly of applicable Atlas Copco oil-free compressors. The official Atlas Copco catalog lists a 4.45 kg kit containing bearings, bushes, gaskets, O-rings, seals, spring, washers, stud, nut and other inlet-valve components.

The inlet valve controls the amount of atmospheric air entering the compressor element. Correct inlet-valve operation is essential for controlling compressor capacity and maintaining proper loading and unloading.

Working Process

1. Air Intake – Atmospheric air reaches the compressor inlet.
2. Inlet Valve Control – The inlet valve regulates the amount of air entering the compressor.
3. Loading – When compressed air is required, the inlet valve opens to allow air into the compression element.
4. Compression – The compressor element compresses the incoming air.
5. Capacity Control – The inlet valve position changes according to compressor demand.
6. Unloading – When the required pressure is reached, the valve moves toward the unloaded position, reducing or stopping air intake.
7. Reloading – When system pressure decreases, the valve opens again.
8. Continuous Regulation – The inlet valve repeatedly adjusts according to operating conditions.

Main Functions

• Services the ZA5 inlet valve assembly.
• Restores correct inlet-valve movement.
• Controls compressor air intake.
• Supports loading and unloading.
• Restores sealing around valve components.
• Reduces unwanted air leakage.
• Supports stable compressor capacity.
• Helps maintain reliable compressor operation.

Kit Components

Atlas Copco’s official listing includes components such as:

• Washer – 2 pcs
• ZR300-425 Inlet Bearing Block Kit – 1 pc
• Kit Valve Inlet ZA5 – 1 pc
• Stud – 1 pc
• Bearing – 1 pc
• Gaskets – 2 pcs
• O-rings
• Nut M12 – 2 pcs
• Roller bearing – 1 pc
• Circlip – 1 pc
• Bush – 2 pcs
• O-ring 104.5 × 3 – 2 pcs
• Seals – 2 pcs
• Compression spring – 1 pc

The exact component list is confirmed in Atlas Copco’s official catalog.

Role of the Inlet Valve

The inlet valve is responsible for regulating the compressor’s intake airflow. When air demand is high, it permits the required amount of air into the compression element.

During unloading, the valve reduces the incoming airflow. This prevents the compressor from continuing to operate at full capacity when compressed air is not required.

A properly functioning inlet valve therefore helps control:

• Compressor capacity
• Air intake
• Loading/unloading
• Energy consumption
• Operating stability

Possible Failure Conditions

The inlet valve assembly may deteriorate because of:

• Normal mechanical wear
• Bearing wear
• Bush wear
• Damaged seals
• Hardened O-rings
• Contamination
• Weak or damaged spring
• Damaged valve components
• Excessive vibration
• Incorrect adjustment

Possible symptoms include:

• Poor loading/unloading.
• Compressor running continuously.
• Reduced compressor capacity.
• Excessive air intake during unloading.
• Increased energy consumption.
• Unstable pressure.
• Air leakage.
• Abnormal compressor operation.

Maintenance Procedure

Before servicing the inlet valve:

1. Shut down the compressor according to the applicable Atlas Copco service procedure.
2. Isolate the electrical supply.
3. Depressurize the compressor.
4. Allow components to cool.
5. Remove the inlet-valve assembly.
6. Inspect the valve, bearings, bushes and sealing surfaces.
7. Remove worn components.
8. Clean all mating surfaces.
9. Install the replacement components from 2906051500.
10. Correctly position the O-rings, gaskets, seals, bushes and bearings.
11. Ensure the valve moves freely.
12. Secure the assembly according to the applicable service procedure.
13. Restart the compressor.
14. Check loading and unloading operation.
15. Check for air leakage and abnormal noise.
16. Monitor compressor pressure and operating conditions.

Service Benefits

Using the 2906051500 ZA5 Inlet Valve Kit during appropriate maintenance helps:

• Restore inlet-valve performance.
• Improve loading/unloading operation.
• Restore valve sealing.
• Reduce air leakage.
• Support efficient compressor operation.
• Improve compressor reliability.
• Reduce unexpected downtime.

Technical Summary

Recommended catalog title: Atlas Copco 2906051500 – ZA5 Inlet Valve Overhaul Kit / Kit Valve Inlet ZA5, 2906-0515-00.

Atlas Copco official product listing

Compatibility: Verify the compressor model and serial number before ordering, as inlet-valve configurations can vary between machines.