Atlas Copco +Z 4++ Check Valve Kit Replacement – R2906018700

Atlas Copco R2906018700 – +Z 4++ Check Valve Kit

The Atlas Copco R2906018700 (2906018700 / 2906-0187-00) Check Valve Kit is a service kit used in ZR/ZT oil-free compressor systems. The check valve controls the direction of compressed-air flow and prevents reverse flow through the compressor circuit.

Working Process:
During normal compressor operation, compressed air generated by the compressor flows toward the downstream air system. When the pressure on the compressor side is higher than the downstream pressure, the check valve opens and allows compressed air to pass through.

The valve operates automatically according to the pressure difference across its internal components. The internal valve mechanism moves to the open position when forward pressure is sufficient, providing a controlled path for compressed-air delivery.

When the compressor unloads or stops, the pressure conditions change. Downstream pressure can become higher than the compressor-side pressure. The check valve then closes automatically, preventing compressed air from flowing backward toward the compressor.

This one-way operation helps protect the compressor from reverse airflow and prevents stored downstream pressure from returning into the compressor stages. It also helps maintain pressure separation between the compressor and downstream system during shutdown and unloading.

The R2906018700 check valve kit is used during preventive maintenance when the valve’s internal wear components require replacement. Atlas Copco’s official listing shows components including 1 spring, 2 rings, 2 spring sleeves, 4 lug bearings, and 2 stop pins, with an official listed kit weight of 136 g.

During maintenance, the compressor must be stopped, isolated, and completely depressurized before the check-valve assembly is opened. The existing components are removed and the valve body, seating surfaces, and flow passages are inspected for wear, contamination, or damage.

The replacement components supplied in the kit are then installed in the correct positions and orientation. Particular attention should be given to the spring, bearings, sleeves, and stop pins to ensure correct valve movement.

After assembly, the check valve should be tested for unrestricted forward flow and positive closing under reverse-pressure conditions. The compressor should then be operated through its normal starting, loading, unloading, and shutdown sequences.

A worn or damaged check valve can cause reverse airflow, pressure loss, unstable operation, increased compressor stress, or incorrect pressure behavior during shutdown. Regular replacement of the service components helps restore proper one-way airflow and reliable compressor operation.

Part Number: R2906018700
Numeric Part Number: 2906018700
Alternative Number: 2906-0187-00 / 2906 0187 00
Part Description: +Z 4++ Check Valve Kit
Brand: Atlas Copco
Application: ZR/ZT oil-free compressors
Component Type: Check / non-return valve service kit
Official Listed Weight: 136 g
Kit Components: Spring, rings, spring sleeves, lug bearings, and stop pins
Primary Function: Allows forward compressed-air flow and prevents reverse flow
Main Benefits: Protects compressor stages, maintains pressure separation, prevents backflow, and supports reliable compressor operation.

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