Atlas Copco Inlet Valve Kit ZR300-425 Replacement – 2906044200

Atlas Copco 2906044200 – Inlet Valve Kit ZR300-425

The Atlas Copco 2906044200 (2906-0442-00) Inlet Valve Kit is a service and replacement kit designed for compatible ZR300–425 oil-free compressors. Its primary function is to maintain accurate control of the compressor’s inlet air flow during loading, unloading and capacity regulation.

Atlas Copco officially identifies the part as “KIT VALVE INLET ZR300-425” for oil-free compressors and lists the kit weight as 1.05 kg.

Working Process:

During compressor operation, atmospheric air enters the compressor through the inlet valve before reaching the compression element.

The inlet valve controls how much air is allowed to enter the compressor. By regulating the inlet opening, the compressor can control its capacity according to the required system pressure and operating condition.

When the compressor needs to produce compressed air, the inlet valve moves toward its open position. This allows the required quantity of atmospheric air to enter the compressor.

As the air demand decreases or the compressor reaches the required system pressure, the control system changes the inlet-valve position. The valve restricts the incoming airflow, reducing the amount of air entering the compression system.

During unloading, the inlet valve moves toward its closed/restricted position. This reduces the compressor’s intake and helps the machine operate with lower compression load.

The 2906044200 service kit contains the sealing and flexible valve components required to restore the inlet-valve mechanism during maintenance.

Atlas Copco’s official component listing includes:

• O-ring 16 × 2 – 2 pcs
• Diaphragm – 1 pc
• Membrane – 1 pc
• O-ring – 2 pcs
• Membrane – 1 pc

The official Atlas Copco catalog lists these components as part of the 2906044200 kit.

The diaphragm and membranes are flexible control components that respond to pneumatic pressure and transmit the control force required for inlet-valve movement.

The O-rings provide airtight sealing between the valve components and their mating surfaces. Proper sealing is essential because the inlet valve relies on controlled pressure to operate correctly.

During compressor operation, the diaphragm and membrane are repeatedly exposed to pressure changes as the compressor transitions between loaded and unloaded conditions.

Over time, flexible components can become hardened, cracked, stretched or permanently deformed. O-rings can also lose elasticity because of temperature, age and operating conditions.

A damaged diaphragm or membrane may cause slow, incomplete or unstable inlet-valve movement.

If the inlet valve does not open correctly, the compressor may receive insufficient intake air, resulting in reduced capacity and abnormal operating conditions.

If the valve does not close correctly during unloading, excessive air may continue entering the compressor. This can increase energy consumption and prevent the compressor from unloading efficiently.

Air leakage through damaged O-rings can also disturb the pneumatic control pressure and cause unreliable valve operation.

Maintenance Procedure:

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

The inlet-valve assembly should be inspected for contamination, damaged diaphragms, worn membranes, deteriorated O-rings, leakage, corrosion and abnormal valve movement.

The old diaphragm, membranes and O-rings should be removed carefully without damaging the valve housing or sealing surfaces.

The 2906044200 Inlet Valve Kit should be used to replace the applicable worn service components.

All sealing surfaces must be thoroughly cleaned before installation.

The supplied O-rings must be installed in their correct grooves without twisting, cutting, overstretching or pinching.

The diaphragm and membranes must be installed in the correct positions and orientations according to the applicable Atlas Copco service procedure.

After assembly, the inlet valve should be checked for smooth and unrestricted movement.

The pneumatic control connections should be inspected for leakage and secure installation.

After reassembly, the compressor should be started and monitored during loading, unloading and normal operation.

The inlet valve should open progressively when the compressor is required to produce air and restrict/close correctly when the compressor unloads.

Correct inlet-valve operation maintains accurate compressor capacity control and helps prevent unnecessary energy consumption.

Using the Atlas Copco 2906044200 Inlet Valve Kit during the appropriate maintenance operation helps restore pneumatic control, sealing performance, inlet-air regulation and reliable loading/unloading behavior.

Part Number: 2906044200
Alternative Number: 2906-0442-00 / 2906 0442 00
Brand: Atlas Copco
Part Description: Inlet Valve Kit
Official Description: Kit Valve Inlet ZR300-425
Application: Atlas Copco ZR300–425 oil-free compressors
Component Type: Inlet valve service kit
Official Listed Weight: 1.05 kg
Main Components: O-rings, diaphragm and membranes
Primary Function: Controls compressor inlet-air flow
Secondary Function: Supports accurate loading, unloading and capacity regulation
Operating Function: Uses pneumatic control pressure to open, restrict or close the compressor inlet
Main Benefits: Reliable inlet control, improved loading/unloading, reduced air leakage, stable compressor capacity and dependable compressor operation.

Disclaimer: All manufacturer names, trademarks, model numbers, and part numbers are used solely for identification and compatibility purposes. Our products are high-quality aftermarket replacement products and are not manufactured, sponsored, endorsed, or authorized by the original equipment manufacturer (OEM). All trademarks remain the property of their respective owners.