Atlas Copco Check Valve Kit / Oil Stop Check Valve Kit Replacement – 2901050300

Atlas Copco 2901050300 – Check Valve Kit / Oil Stop Check Valve Kit

The Atlas Copco 2901050300 (2901-0503-00) Check Valve Kit is a service kit used in the oil and air circuit of Atlas Copco rotary screw compressors. It is specifically referenced for GA50 VSD compressors equipped with the C106EL air end. Its main function is to allow flow in the intended direction while preventing unwanted reverse flow, particularly oil backflow during compressor shutdown and unloading conditions.

Working Process:
During normal compressor operation, the compressor element generates compressed air and the oil-injection system continuously circulates oil for cooling, lubrication, and sealing. The check valve remains open when the pressure conditions are correct, allowing the required flow through the designated circuit.

The valve responds automatically to pressure differences. When the pressure on the upstream side is sufficient, the internal valve mechanism moves against the spring force and permits flow. This allows the compressor’s oil/air circuit to operate normally while maintaining the required pressure balance.

When the compressor unloads or stops, the pressure conditions change. The spring-assisted check valve closes and restricts the passage. This prevents oil and/or compressed fluid from flowing backward into the compressor element or other parts of the circuit. Preventing reverse oil flow is particularly important during shutdown because uncontrolled oil migration can cause oil accumulation and operating problems during subsequent starting.

The 2901050300 kit restores the sealing and closing function of the valve when its service components become worn or damaged. Available parts references list the kit components as one 69.5 × 3 O-ring, one spring, one M16 washer, and three 59.5 × 3 O-rings.

During preventive maintenance, the compressor must be isolated and depressurized before the check-valve assembly is serviced. The old sealing components and other serviceable parts are removed, the valve housing and mating surfaces are cleaned and inspected, and the replacement components are installed correctly.

After installation, the valve should be checked for correct flow direction, proper spring action, and leakage. A correctly functioning check valve opens when forward pressure is available and closes when reverse pressure occurs.

If the check valve becomes worn, contaminated, or unable to seal properly, reverse flow may occur. This can result in oil migration, oil accumulation, pressure loss, increased oil consumption, difficult starting, or reduced compressor reliability.

Regular replacement of the check-valve service components helps maintain proper oil-flow control, prevents unwanted backflow, and supports reliable and efficient compressor operation.

Part Number: 2901050300
Alternative Number: 2901-0503-00 / 2901 0503 00
Part Description: Check Valve Kit / Oil Stop Check Valve Kit
Brand: Atlas Copco
Application: Atlas Copco GA50 VSD with C106EL air end
Component Type: Check / non-return valve service kit
Primary Function: Controls one-way flow and prevents oil backflow
Kit Components: O-rings, spring, and M16 washer
Main Benefits: Prevents reverse oil flow, maintains pressure balance, protects compressor components, and supports reliable operation.

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