Atlas Copco Check Valve Kit Replacement – 2906002100

Atlas Copco 2906002100 – Check Valve Kit

The Atlas Copco 2906002100 (2906-0021-00) Check Valve Kit is a service and repair kit used in compatible Atlas Copco oil-injected screw compressor systems. Its primary function is to allow compressed air or process flow to move in the intended direction while preventing reverse flow when compressor pressure conditions change.

Working Process:

During normal compressor operation, the compressor generates compressed air and sends it through the discharge circuit toward the downstream air system. The check valve permits forward flow when the pressure on the compressor side is higher than the downstream pressure.

The internal valve elements open under the pressure differential, creating a passage for compressed air. The valve remains open while the forward pressure is sufficient to overcome the spring force and sealing resistance.

When the compressor unloads or stops, the pressure relationship changes. Downstream pressure may remain higher than the compressor-side pressure. The internal springs then push the valve elements back onto their seats.

This closes the flow passage and prevents compressed air from returning toward the compressor.

The non-return function is important during compressor shutdown and unloading because it prevents reverse pressurization of the compressor circuit. It also helps maintain pressure separation between the compressor and downstream compressed-air system.

Atlas Copco’s official catalog identifies 2906002100 as a “CV Kit for Oil Injected Screw Compressors” and describes it as a Check Valve Kit. The official specification gives a weight of 410 g.

The official kit contains:

• O-ring 89.5 × 3 – 4 pcs
• O-ring ID 99.5 mm – 1 pc
• Lock washer – 4 pcs
• Valve – 2 pcs
• Compression spring – 2 pcs
• Dowty seal washer 1/2+ – 1 pc

These components work together to restore the mechanical movement and sealing capability of the check-valve assembly.

The valve elements provide the one-way flow function. The compression springs provide the closing force when the forward pressure decreases. The O-rings and Dowty sealing washer prevent leakage around the valve assembly, while the lock washers secure the relevant components during operation.

During compressor operation, the valve components are repeatedly exposed to pressure fluctuations, vibration, temperature changes, and opening/closing cycles. Contaminated oil, dirt, wear, corrosion, or damaged sealing components can prevent the valve from operating correctly.

A worn check valve may remain partially open, allowing reverse airflow after unloading or shutdown. This can cause pressure loss, abnormal pressure equalization, extended unloading behavior, or unwanted pressure migration into the compressor circuit.

If the valve becomes stuck closed or excessively restricted, it can create additional pressure drop and interfere with normal compressed-air delivery.

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

The existing valve components should be removed according to the applicable Atlas Copco service procedure. The valve seats, springs, O-rings, sealing surfaces, and internal passages should be inspected for wear, contamination, corrosion, deformation, or damage.

The replacement components supplied in the 2906002100 kit should be installed in the correct orientation. O-rings must be installed carefully without twisting, cutting, or damaging the sealing surfaces.

After reassembly, the compressor should be operated through its start-up, loaded, unloaded, and shutdown cycles. The check valve should open smoothly during forward flow and close securely when the pressure differential reverses.

Correct operation of the check valve helps protect the compressor from reverse airflow, maintain pressure stability, reduce leakage, and support reliable compressor operation.

Using the Atlas Copco 2906002100 Check Valve Kit during maintenance restores the valve’s one-way flow function and helps extend the service life of the compressor discharge system.

Part Number: 2906002100
Alternative Number: 2906-0021-00 / 2906 0021 00
Brand: Atlas Copco
Part Description: Check Valve Kit / CV Kit
Component Type: Check / non-return valve service kit
Application: Oil-injected screw compressors
Known Applications: GR1120, GR1520, GR110 and GR200 configurations
Official Listed Weight: 410 g
Primary Function: Allows forward compressed-air flow and prevents reverse flow
Kit Components: Valves, compression springs, O-rings, lock washers, and Dowty sealing washer
Main Benefits: Reverse-flow protection, pressure stability, reduced leakage, reliable unloading/shutdown, and dependable compressor operation.

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