Atlas Copco GA90/160 Oil Bypass Valve Kit Replacement – 2906096300

Atlas Copco 2906096300 – GA90/160 Oil Bypass Valve Kit

The Atlas Copco 2906096300 (2906-0963-00) is an Oil Bypass Valve Kit designed for compatible GA90/GA160 oil-injected screw compressors.

The oil bypass valve is part of the compressor’s oil circulation and temperature-control system. It controls the route taken by compressor oil depending on operating conditions, helping ensure that the oil reaches the compressor element at the appropriate temperature.

Working Process:

During operation of an oil-injected screw compressor, lubricating oil performs several important functions. It provides lubrication to moving components, removes heat generated during compression, and contributes to sealing between the screw rotors.

After leaving the compressor element, the oil is separated from the compressed-air/oil mixture and circulated through the compressor’s oil system.

The oil temperature must be controlled within the required operating range.

The 2906096300 oil bypass valve kit helps control oil flow between the relevant oil-circuit paths.

During cold start-up, the oil may be below its normal operating temperature. The bypass arrangement allows the oil to avoid unnecessary passage through the oil cooler or follow the required bypass route, helping the oil reach operating temperature more quickly.

As the compressor warms up, the valve responds to the oil-temperature condition and changes the oil-flow path.

When cooling is required, a greater portion of the oil can be directed through the oil cooler before returning to the compressor element.

This controlled circulation helps maintain suitable oil temperature during continuous compressor operation.

Main Functions:

• Controls oil flow through the compressor oil circuit.
• Provides the required bypass function during oil-temperature changes.
• Helps accelerate oil warm-up during cold operation.
• Helps prevent excessive oil temperature during continuous operation.
• Supports correct lubrication of the compressor element.
• Helps maintain oil viscosity within the required operating range.
• Supports reliable compressor performance.
• Helps protect oil-lubricated components from unsuitable operating conditions.

Oil-Circulation Process:

1. Compressor Start: The compressor starts and the screw element begins rotating.
2. Oil Circulation: Lubricating oil begins circulating through the compressor oil system.
3. Cold Condition: Oil temperature is initially below normal operating temperature.
4. Bypass Operation: The bypass valve directs oil through the appropriate bypass path.
5. Rapid Warm-Up: Oil reaches operating temperature more efficiently.
6. Temperature Increase: Continuous compression causes the oil temperature to rise.
7. Valve Response: The bypass valve changes the oil-flow path according to the temperature condition.
8. Cooling: Oil requiring cooling is directed through the oil cooler.
9. Return: Conditioned oil returns to the compressor element.
10. Continuous Regulation: The valve continues controlling the oil circuit as operating conditions change.

Importance of the Oil Bypass Valve:

Correct oil temperature is important in an oil-injected screw compressor.

If the oil remains too cold, water condensation and poor oil circulation can become concerns, while excessive oil temperature can accelerate oil degradation and reduce lubrication effectiveness.

The bypass valve therefore helps the compressor manage oil temperature during changing operating conditions.

A properly functioning valve allows the oil system to transition between bypass and cooling conditions as required.

Possible Failure Conditions:

A worn, contaminated or malfunctioning oil bypass valve can affect oil circulation.

Possible conditions include:

• Valve sticking.
• Restricted valve movement.
• Damaged valve components.
• Contamination inside the valve.
• Incorrect bypass operation.
• Internal leakage.
• Restricted oil flow.
• Incorrect oil temperature regulation.

Possible compressor symptoms may include:

• Slow oil warm-up.
• Excessively low oil temperature.
• Excessively high oil temperature.
• Unstable oil temperature.
• Reduced compressor efficiency.
• Increased oil degradation.
• Lubrication-related problems.
• Oil-circuit temperature alarms.
• Abnormal compressor operating conditions.

These symptoms should be diagnosed carefully because oil-temperature problems can also originate from the oil cooler, thermostat, oil filter, oil passages, temperature sensor or other components.

Maintenance Procedure:

Before servicing the oil bypass valve, stop the compressor, isolate the electrical supply and depressurize the compressor according to the applicable Atlas Copco safety procedure.

Allow the compressor and oil to cool sufficiently before beginning maintenance.

Inspect the oil bypass valve assembly for:

• Contamination
• Wear
• Valve sticking
• Damaged sealing surfaces
• Internal leakage
• Restricted movement
• Damaged components

Remove the existing valve/service components carefully.

Clean the relevant valve housing and mating surfaces.

Install the replacement components supplied with the 2906096300 Oil Bypass Valve Kit according to the applicable Atlas Copco service documentation.

Ensure that:

• Valve components are correctly positioned.
• Sealing components are correctly installed.
• The valve moves freely.
• Oil passages are clean.
• Connections are properly secured.
• No components are damaged during assembly.

After assembly, restore the compressor oil circuit and perform the applicable checks.

Restart the compressor and monitor the oil-temperature behavior during:

• Cold start
• Warm-up
• Normal loaded operation
• Unloaded operation

Check for oil leakage and verify that the compressor reaches and maintains its normal operating temperature.

Service Benefits:

Using the 2906096300 Oil Bypass Valve Kit during appropriate maintenance helps restore the correct oil-flow control function.

A properly functioning bypass valve supports:

• Correct oil warm-up.
• Stable oil temperature.
• Effective compressor lubrication.
• Proper oil cooling.
• Reduced risk of oil degradation.
• Reliable compressor operation.
• Longer service life of oil-lubricated components.

Part Number: 2906096300
Alternative Number: 2906-0963-00 / 2906 0963 00
Brand: Atlas Copco
Official/Parts Description: Oil Bypass Valve Kit / Bypass Valve Kit
Application: Atlas Copco GA90/GA160 oil-injected screw compressors
Component Type: Oil-circuit control/service kit
Primary Function: Controls the oil bypass flow path
Secondary Function: Supports oil-temperature regulation
Operating Function: Directs oil through the appropriate bypass/cooling path according to operating conditions
Main Benefits: Faster oil warm-up, controlled oil temperature, reliable lubrication, reduced oil degradation and dependable compressor operation.

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