Atlas Copco Check Valve Kit Replacement – 2906039000

Atlas Copco 2906039000 – Check Valve Kit

The Atlas Copco 2906039000 (2906-0390-00) Check Valve Kit is a service and maintenance kit used in compatible ZR and ZT oil-free compressors. Its primary function is to allow compressed air to flow in the correct direction while preventing reverse airflow from the downstream system back toward the compressor.

Working Process:

During normal compressor operation, compressed air generated by the compressor flows through the discharge circuit toward the downstream air network. The check valve opens when the pressure on the compressor side becomes higher than the downstream pressure, allowing compressed air to pass through.

The internal valve elements respond to the pressure differential. Once the forward pressure is sufficient to overcome the spring force and sealing resistance, the valve moves away from its seat and establishes the required flow passage.

During loaded operation, the valve remains open and allows compressed air to move toward the downstream system while maintaining the required pressure separation between the compressor and the air network.

When the compressor unloads or stops, the pressure conditions change. Downstream pressure may remain higher than the compressor-side pressure. The internal springs then return the valve elements toward their seats.

The valve closes and prevents compressed air from flowing backward into the compressor discharge system. This non-return function is particularly important during shutdown and unloading because it prevents unwanted reverse pressurization and pressure equalization through the compressor.

Atlas Copco’s official catalog identifies 2906039000 as “KIT VALVE CHECK FOR ZR ZT OIL FREE COMPRESSORS.” The official listing gives a total kit weight of 2.71 kg.

The official component list includes:

• Valve – 3 pcs
• Spring – 2 pcs
• Bushing – 1 pc
• O-ring – 1 pc
• O-ring 92.3 × 5.7 – 3 pcs
• O-ring 289.3 × 5.7 – 1 pc
• O-ring 99.1 × 5.7 – 1 pc

These components work together to restore the check valve’s movement, pressure response, and sealing performance.

The valves provide the primary one-way flow-control function. The springs provide closing force when forward pressure decreases. The bushing supports correct positioning and movement, while the O-rings provide sealing between the valve assembly and its housing.

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

A worn or damaged check valve may allow compressed air to flow backward after the compressor unloads or stops. This can result in pressure loss, abnormal shutdown behavior, unwanted pressure equalization, and additional stress on compressor components.

If the valve becomes stuck closed or excessively restricted, it can create increased 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 valve assembly should be dismantled according to the applicable Atlas Copco maintenance procedure. The valve elements, springs, bushing, O-rings, valve seats, and internal passages should be inspected for wear, contamination, corrosion, deformation, and damage.

The worn components should be replaced using the 2906039000 Check Valve Kit. All O-rings must be installed carefully without twisting, cutting, or damaging the sealing surfaces. The valves, springs, and bushing must be installed in their correct positions and orientations.

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.

Correct operation of the check valve helps maintain 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 2906039000 Check Valve Kit during scheduled maintenance helps restore reliable one-way airflow control, proper sealing, stable pressure behavior, and dependable oil-free compressor operation.

Part Number: 2906039000
Alternative Number: 2906-0390-00 / 2906 0390 00
Brand: Atlas Copco
Part Description: Check Valve Kit
Official Description: Kit Valve Check for ZR/ ZT Oil-Free Compressors
Component Type: Check / non-return valve service kit
Application: Atlas Copco ZR and ZT oil-free compressors
Official Listed Weight: 2.71 kg
Primary Function: Allows forward compressed-air flow and prevents reverse flow
Main Components: Valves, springs, bushing, and multiple O-rings
Operating Function: Controls one-way compressed-air flow during normal operation, unloading, and shutdown
Main Benefits: Reverse-flow protection, pressure stability, reliable sealing, reduced leakage, compressor protection, and dependable 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.