Atlas Copco HP Discharge Silencer Kit Replacement – 2906066200

The Atlas Copco 2906066200 is an HP (High-Pressure) Discharge Silencer Kit used in the discharge section of ZT55–90 oil-free compressors. Its function is to reduce noise and pressure pulsations produced when compressed air exits the high-pressure compression stage.

The kit contains the silencing insulation and replacement O-rings required for servicing the HP discharge silencer. Atlas Copco lists the kit weight as 1.79 kg.

Working Process

1. HP Compression – Air is compressed in the high-pressure compressor element.
2. HP Discharge – High-pressure air leaves the HP compression stage.
3. Pulsation & Noise – The discharged air creates pressure pulsations and aerodynamic noise.
4. Silencer Action – The discharge silencer reduces these pressure pulsations and attenuates noise.
5. Insulation – The silencing insulation helps reduce transmitted acoustic energy.
6. Sealing – O-rings maintain airtight connections around the silencer.
7. Downstream Flow – The treated compressed air continues toward the cooler and outlet system.

Kit Components

Atlas Copco’s official Web Shop lists:

Main Functions

• Reduces HP discharge noise.
• Dampens pressure pulsations.
• Helps provide smoother downstream airflow.
• Maintains proper sealing of the discharge connection.
• Replaces deteriorated silencing insulation and O-rings.
• Supports reliable operation of the ZT55–90 compressor.

Possible Failure Symptoms

A damaged or deteriorated HP discharge silencer can result in:

• Increased compressor noise.
• Excessive discharge pulsation.
• Abnormal vibration.
• Damaged silencer insulation.
• Air leakage around connections.
• Increased acoustic levels near the compressor.

Maintenance Procedure

1. Shut down the compressor according to the applicable Atlas Copco service procedure.
2. Isolate the electrical supply.
3. Fully depressurize the HP discharge system.
4. Allow the compressor to cool.
5. Access the HP discharge silencer.
6. Inspect the silencer housing and insulation.
7. Remove worn O-rings and damaged insulation.
8. Clean the sealing surfaces.
9. Install the components supplied with 2906066200.
10. Ensure the O-rings are correctly seated.
11. Reassemble the silencer and connections.
12. Restart the compressor.
13. Check for air leakage and abnormal noise.
14. Verify normal compressor operation.

Technical Summary

Recommended catalog title:
Atlas Copco 2906066200 – ZT55–90 HP Discharge Silencer Kit, 2906-0662-00.

Related Parts

The same ZT55–90 parts sequence includes 2906066100 – ZR/T55–90 Oil Pump Kit immediately before this part and 2906066300 – ZT55–90 Cooler Service Kit immediately after it.

Note: For ordering, verify the compressor model and serial number, because the closely related ZR55–90 range uses a different HP discharge silencer kit (2906067200).