Atlas Copco Check Valve Kit Replacement – 2906037400

Atlas Copco 2906037400 – Check Valve Kit

The Atlas Copco 2906037400 (2906-0374-00) Check Valve Kit is a service and maintenance kit designed for compatible Atlas Copco oil-free compressor systems. Its primary function is to control the direction of compressed-air flow and prevent reverse airflow from the downstream system back toward the compressor.

Working Process:

During normal compressor operation, the compressor generates compressed air and sends it through the discharge system toward the downstream air network. The check valve allows compressed air to flow in the intended direction while preventing flow in the opposite direction.

When the pressure at the compressor outlet becomes higher than the downstream pressure, the pressure differential acts on the internal valve element and opens the check valve. Compressed air can then pass through the valve toward the downstream system.

As long as forward pressure is maintained, the valve remains in the open position, allowing the required compressed-air flow with minimum restriction.

When the compressor unloads or stops, the pressure relationship changes. Downstream pressure can remain higher than the pressure on the compressor side. The internal spring then assists in returning the valve to its closed position.

The valve closes against its sealing surface and prevents compressed air from flowing backward toward the compressor.

This non-return function is important because it prevents reverse pressurization of the compressor discharge circuit. It also helps protect internal compressor components and prevents unwanted pressure equalization through the compressor during unloading and shutdown.

Atlas Copco’s official catalog identifies 2906037400 specifically as “CHECK VALVE KIT FOR OIL FREE COMPRESSORS.” The official listing gives a weight of 1.64 kg.

The official component list includes:

• O-ring 84.1 × 5.7 – 1 pc
• O-ring – 1 pc
• O-ring 64.3 × 5.7 – 2 pcs
• O-ring – 1 pc
• Spring – 1 pc
• O-ring – 1 pc
• Valve – 1 pc
• Valve – 1 pc
• Bushing – 1 pc
• O-ring 79.2 × 5.7 – 3 pcs

These components work together to restore the valve’s movement, sealing, and one-way flow characteristics.

The valve elements provide the primary flow-control function. The spring provides closing force when forward pressure decreases. The O-rings provide sealing between the valve components and housing, while the bushing maintains the correct positioning and movement of the valve assembly.

During continuous compressor operation, the check valve is exposed to pressure fluctuations, vibration, temperature changes, and repeated opening and closing cycles. Contamination, wear, damaged sealing surfaces, or deteriorated O-rings can prevent the valve from sealing correctly.

A defective check valve may remain partially open after compressor shutdown. This can allow downstream compressed air to flow backward into the compressor circuit, resulting in pressure loss, abnormal shutdown behavior, unwanted pressure equalization, or increased mechanical stress.

If the valve becomes stuck closed or excessively restricted, it can create additional pressure drop and reduce the compressor’s ability to deliver compressed air efficiently.

During maintenance, the compressor must be stopped, electrically isolated, completely depressurized, and allowed to cool before the check-valve assembly is serviced.

The valve assembly should be dismantled according to the applicable Atlas Copco maintenance procedure. The valve elements, spring, bushing, O-rings, valve seats, and internal passages should be inspected for wear, contamination, corrosion, deformation, or damage.

The worn components should be replaced using the 2906037400 Check Valve Kit. All O-rings must be installed carefully without twisting, cutting, or damaging the sealing surfaces. The spring, valve elements, and bushing must be installed in their correct orientation.

After reassembly, the compressor should be checked for leakage and operated through its complete start-up, loaded, unloaded, and shutdown sequence.

During testing, the check valve should open smoothly when forward pressure is established and close securely when the pressure differential reverses.

A correctly functioning check valve maintains proper pressure separation between the compressor and downstream system, prevents reverse airflow, reduces leakage, and protects the compressor during unloading and shutdown.

Using the Atlas Copco 2906037400 Check Valve Kit during scheduled maintenance helps restore reliable one-way airflow control, proper sealing, pressure stability, and dependable compressor operation.

Part Number: 2906037400
Alternative Number: 2906-0374-00 / 2906 0374 00
Brand: Atlas Copco
Part Description: Check Valve Kit for Oil-Free Compressors
Component Type: Check / non-return valve service kit
Application: Atlas Copco oil-free compressor systems
Official Listed Weight: 1.64 kg
Primary Function: Allows forward compressed-air flow and prevents reverse flow
Main Components: Valve elements, spring, bushing, and multiple O-rings
Operating Function: Controls one-way compressed-air flow during loading, unloading, and shutdown
Main Benefits: Reverse-flow protection, pressure stability, reliable sealing, reduced leakage, compressor protection, and dependable operation.

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