Atlas Copco Inlet Valve Service Kit for ZR/ZT Compressors Replacement – 2906039100

Atlas Copco 2906039100 – Inlet Valve Service Kit for ZR/ZT Compressors

The Atlas Copco 2906039100 (2906-0391-00) is an Inlet Valve Service Kit designed for compatible ZR/ZT oil-free screw compressors. Parts references specifically identify the kit for the ZR/ZT 160–275 compressor range.

The inlet valve is an important component of the compressor’s air-intake and capacity-control system. It regulates the amount of atmospheric air entering the compressor element according to the compressor’s operating requirements.

Working Process:

During compressor operation, atmospheric air enters through the compressor inlet system.

When compressed-air production is required, the control system positions the inlet valve toward the open operating position. This allows the required quantity of air to enter the compressor element.

The compressor element compresses the incoming air and delivers it through the compressor’s subsequent stages and discharge system.

When the compressor reaches the required operating condition or the control system requests reduced capacity, the inlet valve changes position.

The valve restricts the incoming airflow, reducing the amount of air supplied to the compression element. This reduces compressor output and prevents unnecessary compression during periods of lower demand.

When compressed-air demand increases, the control system changes the inlet-valve control signal.

The inlet valve moves back toward its operating position, allowing increased airflow into the compressor element and restoring the required compressor capacity.

This controlled inlet-air process allows the compressor to automatically adapt its output to changing compressed-air demand.

Main Functions:

• Controls atmospheric air entering the compressor.
• Regulates compressor capacity.
• Supports loading and unloading operation.
• Controls inlet airflow according to system demand.
• Helps maintain stable compressor operation.
• Reduces unnecessary air intake during reduced-capacity operation.
• Restores inlet-valve sealing and operating performance during servicing.

Operating Cycle:

1. Start-up: The inlet valve is placed in its required starting position.
2. Loading: The valve permits atmospheric air to enter the compressor element.
3. Compression: The compressor element compresses the incoming air.
4. Pressure/Capacity Control: The compressor controller monitors operating conditions.
5. Capacity Reduction: The inlet valve moves toward a restricted position when less air is required.
6. Reduced Air Intake: Compressor output decreases.
7. Demand Increase: The controller requests additional compressor capacity.
8. Valve Reopening: The inlet valve moves toward the open operating position.
9. Normal Operation: Increased airflow enters the compressor element and compressor capacity is restored.

The process is automatically controlled according to the compressor’s operating requirements.

Service Kit Function:

The 2906039100 service kit is used during maintenance when components of the inlet-valve assembly have become worn, contaminated or deteriorated.

The kit helps restore the valve’s sealing characteristics and correct operating movement.

Replacing service components helps reduce unwanted leakage and ensures that the inlet valve responds correctly to the compressor’s control system.

A correctly serviced valve should move smoothly and maintain the required sealing performance throughout repeated operating cycles.

Possible Failure Conditions:

Continuous compressor operation can cause inlet-valve components to experience wear, contamination, seal deterioration or mechanical sticking.

Potential symptoms include:

• Compressor fails to load correctly.
• Compressor fails to unload or reduce capacity correctly.
• Reduced compressed-air delivery.
• Slow pressure build-up.
• Unstable compressor operation.
• Incorrect compressor capacity.
• Excessive air consumption.
• Delayed inlet-valve response.
• Pneumatic or air leakage.
• Valve sticking.
• Abnormal capacity-control cycling.

If the inlet valve remains too restricted during loading, insufficient air can enter the compressor element and compressor output may decrease.

If the valve remains too open during reduced-load operation, the compressor may continue processing more air than required, increasing energy consumption.

Maintenance Procedure:

Before servicing the inlet valve, the compressor must be stopped, electrically isolated and completely depressurized according to the applicable Atlas Copco safety procedure.

Inspect the inlet-valve assembly for:

• Damaged sealing components
• Worn valve components
• Contamination
• Mechanical wear
• Restricted movement
• Valve sticking
• Air or control leakage
• Damaged mating surfaces
• Abnormal load/unload response

Remove the worn service components carefully without damaging the valve body or sealing surfaces.

Install the 2906039100 Inlet Valve Service Kit according to the applicable Atlas Copco service documentation.

Clean all mating and sealing surfaces before assembly.

Install replacement sealing components correctly without twisting, cutting, overstretching or pinching them.

Ensure all valve components are correctly positioned and secured.

Check the valve mechanism for smooth and unrestricted movement.

After assembly, restart the compressor and observe several operating cycles.

Verify that:

• The inlet valve responds correctly to control commands.
• The compressor loads normally.
• The compressor unloads or reduces capacity correctly.
• Air delivery is normal.
• Operating pressure remains stable.
• No abnormal leakage is present.
• Valve movement is smooth.
• The compressor responds correctly to changes in air demand.

A properly serviced inlet valve provides reliable control of airflow entering the compressor element and supports efficient and stable operation.

Using the Atlas Copco 2906039100 Inlet Valve Service Kit during appropriate maintenance helps restore valve sealing, airflow regulation, mechanical movement and reliable compressor capacity control.

Part Number: 2906039100
Alternative Number: 2906-0391-00 / 2906 0391 00
Brand: Atlas Copco
Description: Kit-Service: Inlet Valve ZR/ZT
Also Referenced As: Inlet Valve Kit / Inlet Valve Service Kit
Application: ZR/ZT oil-free screw compressors
Known Application: ZR/ZT 160–275
Component Type: Inlet valve service/maintenance kit
Primary Function: Controls airflow entering the compressor element
Secondary Function: Supports compressor capacity and loading/unloading control
Operating Function: Regulates inlet airflow according to compressor control requirements
Main Benefits: Reliable inlet-air control, improved sealing, stable compressor capacity, proper load/unload response and dependable compressor operation.

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