Atlas Copco ZR300–425 Aftercooler Kit Replacement – 2906044700

Atlas Copco 2906044700 – ZR300–425 Aftercooler Kit

The Atlas Copco 2906044700 (2906-0470-00) is a ZR300–425 Aftercooler Kit designed for compatible Atlas Copco oil-free compressor systems.

The aftercooler is installed after the final compression stage and is responsible for removing heat from the compressed air before it enters the downstream compressed-air system.

During compression, air temperature increases significantly. The aftercooler transfers this excess heat to the applicable cooling medium, reducing the compressed-air temperature and helping maintain stable compressor operation.

The 2906044700 service kit provides replacement sealing and associated components required when servicing the ZR300–425 aftercooler assembly.

Working Process:

During normal compressor operation, atmospheric air enters the compressor and passes through the compression stages.

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

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

Inside the aftercooler, heat is transferred from the compressed air to the cooling medium.

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

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

Maintaining the correct compressed-air temperature helps protect downstream equipment and supports reliable compressor operation.

During scheduled maintenance, the existing aftercooler seals and associated service components are inspected.

Worn or deteriorated O-rings, sealing rings and washers are replaced using the 2906044700 Aftercooler Kit.

This restores the sealing integrity of the aftercooler and helps prevent leakage during continued operation.

Main Functions:

• Supports servicing of the ZR300–425 aftercooler.
• Removes heat from compressed air after final compression.
• Reduces compressed-air discharge temperature.
• Helps protect downstream air-treatment equipment.
• Supports stable compressor operating temperature.
• Restores sealing at aftercooler connections.
• Helps prevent air and cooling-medium leakage.
• Supports reliable oil-free compressor operation.

Official Kit Information:

Atlas Copco lists the product as “ZR300-425 AFTERCOOLER KIT” with an official listed weight of 1.36 kg.

The official component list includes:

• O-ring – 2 pcs
• O-ring – 1 pc
• O-ring – 1 pc
• O-ring – 1 pc
• O-ring – 2 pcs
• Ring – 2 pcs
• Plug 1/4 A A – 2 pcs
• O-ring – 2 pcs
• Seal Ring – 1 pc
• O-ring 79.2 × 5.7 – 1 pc
• O-ring 279.3 × 5.7 – 1 pc
• Seal Washer Dowty 1/4 – 2 pcs

Aftercooler Operating Cycle:

1. Air Intake: Atmospheric air enters the compressor.
2. Compression: Air passes through the compressor stages.
3. Temperature Increase: Compression raises 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: The compressed-air temperature decreases.
8. Cooled-Air Outlet: Conditioned compressed air leaves the aftercooler.
9. Downstream Delivery: Cooled air proceeds to the air-treatment/distribution system.
10. Continuous Cooling: The cycle continues while the compressor operates.

Importance of the Aftercooler:

The final compression stage produces high-temperature compressed air. Effective aftercooling is therefore important for maintaining acceptable downstream temperatures.

A contaminated, restricted or damaged aftercooler may result in:

• Increased discharge temperature.
• Reduced cooling efficiency.
• Increased thermal stress.
• Higher downstream temperature.
• High-temperature alarms.
• Increased energy consumption.
• Reduced compressor reliability.
• Possible thermal shutdown.

Maintaining the aftercooler in good condition helps the compressor operate within its intended temperature range.

Role of O-Rings:

The O-rings supplied in the kit seal the applicable aftercooler joints and connections.

Over time, O-rings can suffer from:

• Hardening
• Compression set
• Loss of elasticity
• Cracking
• Thermal ageing
• Mechanical damage

Replacing the O-rings during service restores the sealing condition of the assembly.

Role of Seal Ring:

The seal ring provides sealing at its designated aftercooler connection.

Correct positioning and seating are essential to prevent leakage when the assembly is pressurized.

Role of Dowty Washer:

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

They combine a metal support washer with an elastomer sealing element, creating a reliable seal when correctly installed and tightened.

Role of Rings and Plugs:

The rings support the applicable mechanical/sealing arrangement within the aftercooler assembly.

The two 1/4 A A plugs close designated openings and help maintain the integrity of the applicable circuit.

Possible Failure Conditions:

Aftercooler performance can deteriorate because of:

• Dust or dirt accumulation.
• Fouling of heat-transfer surfaces.
• Restricted cooling-medium flow.
• Corrosion.
• Mechanical damage.
• Damaged O-rings.
• Deteriorated sealing rings.
• Incorrect assembly.
• Leakage.
• Thermal cycling.

Possible symptoms include:

• High discharge-air temperature.
• Reduced cooling performance.
• Air leakage.
• Cooling-medium leakage.
• High-temperature alarms.
• Increased downstream temperature.
• Increased compressor energy consumption.
• Reduced compressor performance.

Similar symptoms may also originate from fans, cooling-water systems, sensors, valves or other cooling components and should therefore be diagnosed systematically.

Maintenance Procedure:

Before servicing the aftercooler, stop the compressor according to 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 assembly for:

• Dirt accumulation.
• Blocked passages.
• Corrosion.
• Leakage.
• Damaged O-rings.
• Damaged sealing surfaces.
• Mechanical damage.
• Reduced cooling performance.

Remove the old service components carefully.

Clean all mating and sealing surfaces.

Install the replacement components from the 2906044700 Aftercooler Kit.

During assembly:

• Use the correct O-ring at each location.
• Ensure O-rings are correctly seated.
• Do not twist or damage O-rings.
• Install the seal ring correctly.
• Position rings correctly.
• Install the plugs in their designated locations.
• Install Dowty washers correctly.
• Keep cooling and air passages clean.
• Tighten connections according to the applicable Atlas Copco service procedure.

After reassembly, 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 2906044700 Aftercooler Kit during appropriate maintenance helps:

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

Part Number: 2906044700
Alternative Number: 2906-0470-00 / 2906 0470 00
Brand: Atlas Copco
Official Description: ZR300–425 Aftercooler Kit
Application: ZR300–425 oil-free compressors
Official Listed Weight: 1.36 kg
Component Type: Aftercooler service kit
Primary Function: Supports servicing and sealing of the aftercooler assembly
Operating Function: Removes heat from compressed air after final compression
Main Components: O-rings, seal ring, rings, plugs and Dowty seal washers
Main Benefits: Reduced compressed-air temperature, reliable sealing, effective cooling and dependable compressor operation.

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