Atlas Copco Aftercooler Kit Replacement – 2906039500

Atlas Copco 2906039500 – Aftercooler Kit

The Atlas Copco 2906039500 (2906-0395-00) is an Aftercooler Kit for ZR/ZT oil-free compressors, used to service the aftercooling system after the final compression stage.

The aftercooler removes heat from compressed air after it leaves the final compression stage. This reduces the compressed-air temperature before the air enters the downstream compressed-air network.

Atlas Copco lists the kit weight as approximately 500 g and specifies multiple O-rings, plugs and Dowty sealing washers as kit components.

Working Process:

During normal operation, atmospheric air enters the ZR/ZT oil-free compressor and passes through the compression stages.

As air is compressed, its pressure and temperature increase significantly.

After the final compression stage, the hot compressed air enters the aftercooler.

The aftercooler transfers heat from the compressed air to the applicable cooling medium.

As heat is removed, the compressed-air temperature decreases.

The cooled compressed air then continues toward the downstream air-treatment and distribution system.

The reduction in temperature is important because excessively hot compressed air can increase thermal stress on downstream equipment and may carry more moisture in vapor form.

During maintenance, the 2906039500 Aftercooler Kit provides replacement sealing components required to restore the aftercooler assembly.

The replacement O-rings and Dowty washers maintain leak-tight connections, while the plugs seal the applicable service openings.

Main Functions:

• Supports servicing of the compressor aftercooler.
• Helps remove heat from compressed air after final compression.
• Reduces compressed-air discharge temperature.
• Supports proper downstream air conditioning.
• Helps protect downstream equipment from excessive temperature.
• Restores sealing at aftercooler connections.
• Helps prevent compressed-air or cooling-medium leakage.
• Supports reliable ZR/ZT compressor operation.

Official Kit Components:

Atlas Copco’s official catalog lists the following components:

• O-ring – 1 pc
• Plug 1/4 A A – 2 pcs
• O-ring 219.3 × 5.7 – 2 pcs
• O-ring – 1 pc
• O-ring – 1 pc
• O-ring – 3 pcs
• O-ring – 1 pc
• O-ring 279.3 × 5.7 – 2 pcs
• Seal Washer Dowty 1/4 – 2 pcs
• O-ring – 1 pc

The official listed kit weight is 500 g.

Aftercooler Operating Cycle:

1. Air Intake: Atmospheric air enters the compressor.
2. Compression: Air passes through the compression stages.
3. Temperature Increase: Compression increases the air temperature.
4. Final Compression: Air reaches the required final pressure.
5. Aftercooler Entry: Hot compressed air enters the aftercooler.
6. Heat Transfer: Heat moves from the compressed air to the cooling medium.
7. Temperature Reduction: Compressed-air temperature decreases.
8. Cooled-Air Outlet: The conditioned air leaves the aftercooler.
9. Downstream Delivery: Cooled compressed air moves toward the air-treatment/distribution system.
10. Continuous Operation: The cooling process continues while the compressor operates.

Importance of the Aftercooler:

Aftercooling is essential because the final compression stage produces high-temperature compressed air.

If aftercooling performance deteriorates, possible effects include:

• Increased discharge-air temperature.
• Higher downstream operating temperature.
• Increased thermal stress.
• Reduced cooling efficiency.
• Increased moisture-related problems.
• Higher load on downstream air-treatment equipment.
• High-temperature alarms.
• Compressor shutdown.

Maintaining clean heat-transfer surfaces and leak-tight connections helps the aftercooler operate effectively.

Role of O-Rings:

The O-rings supplied in the kit provide sealing between applicable aftercooler components and connections.

During service, old O-rings may become:

• Hardened
• Flattened
• Brittle
• Cracked
• Permanently compressed
• Damaged during disassembly

Replacing them helps restore the sealing integrity of the aftercooler assembly.

Role of Dowty Washers:

The Dowty 1/4 seal washers provide sealing at applicable threaded connections.

They combine a metallic support section with an elastomer sealing element.

When tightened correctly, the sealing element forms a pressure-resistant barrier against leakage.

Role of Plugs:

The two 1/4 A A plugs close applicable openings in the aftercooler assembly.

Correct installation prevents unwanted leakage and maintains the integrity of the relevant circuit.

Possible Failure Conditions:

Aftercooler performance or sealing can deteriorate because of:

• Dust and contamination.
• Fouling of heat-transfer surfaces.
• Restricted cooling-medium flow.
• Corrosion.
• Mechanical damage.
• Damaged O-rings.
• Incorrect assembly.
• Leakage.
• Thermal cycling.

Possible symptoms include:

• High discharge temperature.
• Reduced cooling performance.
• Air leakage.
• Cooling-medium leakage.
• High-temperature alarms.
• Increased downstream temperature.
• Reduced compressor efficiency.
• Increased thermal stress.

These symptoms should be diagnosed carefully because similar conditions can originate from fans, cooling-water systems, temperature sensors, restricted airflow or other components.

Maintenance Procedure:

Before servicing the aftercooler, stop the compressor using the normal shutdown procedure.

Isolate the electrical supply and applicable pneumatic/cooling energy sources.

Depressurize the relevant circuits and allow the aftercooler to cool to a safe service temperature.

Inspect the aftercooler for:

• Dirt accumulation.
• Blocked passages.
• Corrosion.
• Leakage.
• Damaged connections.
• Damaged seals.
• Mechanical damage.
• Reduced cooling performance.

Remove the old sealing components.

Clean all mating and sealing surfaces.

Install the replacement components from the 2906039500 Aftercooler Kit.

During assembly:

• Select the correct O-ring for each location.
• Ensure O-rings are correctly seated.
• Do not twist or cut the O-rings.
• Install the Dowty washers correctly.
• Install the plugs in their designated positions.
• Ensure all mating surfaces are clean.
• Secure connections according to the applicable Atlas Copco service procedure.
• Ensure cooling passages remain unobstructed.

After assembly, perform the required leak and functional checks.

Restart the compressor and allow it to reach normal operating conditions.

Monitor:

• Final discharge temperature.
• Aftercooler performance.
• Cooling-medium flow.
• Air pressure.
• Air leakage.
• Cooling-medium leakage.
• Downstream air temperature.
• Overall compressor stability.

Service Benefits:

Using the Atlas Copco 2906039500 Aftercooler Kit during appropriate maintenance helps:

• Restore aftercooler sealing.
• Maintain effective heat transfer.
• Reduce compressed-air temperature.
• Reduce leakage.
• Protect downstream components.
• Support stable compressor operation.
• Reduce thermal stress.
• Maintain reliable cooling performance.
• Reduce the possibility of unplanned downtime.

Part Number: 2906039500
Alternative Number: 2906-0395-00 / 2906 0395 00
Brand: Atlas Copco
Official Description: Aftercooler Kit for ZR/ZT Oil-Free Compressors
Component Type: Aftercooler service kit
Official Listed Weight: 500 g
Primary Function: Supports servicing and sealing of the compressor aftercooler
Operating Function: Removes heat from compressed air after final compression
Main Components: O-rings, plugs and Dowty seal washers
Main Benefits: Reduced compressed-air temperature, reliable sealing, improved cooling performance and dependable compressor operation.

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