1. Important Safety Information
Please read all instructions carefully before installing and operating this product. Failure to follow these instructions may result in damage to the product, your system, or personal injury.
- Ensure your system is powered off and unplugged from the wall outlet before installation.
- Handle components with care to avoid damage.
- Do not open the liquid cooler's pump or radiator; it contains coolant that should not be ingested or come into contact with skin.
- Keep out of reach of children.
- Only use the provided mounting hardware.
- Consult a qualified technician if you are unsure about any part of the installation process.
2. Package Contents
Verify that all components are present and undamaged before proceeding with installation.
- MasterLiquid 240 Atmos Stealth AIO Liquid Cooler (Radiator with 2x Mobius 120 Black Fans pre-installed, Pump/Cold Plate)
- Intel Mounting Brackets (LGA 1851/1700/1200/115x)
- AMD Mounting Brackets (AM5/AM4)
- Backplate (for Intel sockets)
- Mounting Screws and Standoffs
- Thermal Paste (pre-applied or in a tube)
- Fan and Pump Cables
- Tube Clips for cable management
- User Manual (this document)
Figure 2.1: Overview of the MasterLiquid 240 Atmos Stealth packaging and included accessories, showing separate compartments for Intel and AMD mounting hardware.
3. Setup and Installation
This section provides detailed instructions for installing the MasterLiquid 240 Atmos Stealth CPU Liquid Cooler on both Intel and AMD platforms. Ensure your motherboard is compatible with the cooler's mounting brackets.
3.1. Preparation
- Power off your computer and unplug the power cable.
- Open your computer case and locate the CPU socket area.
- Remove any existing CPU cooler. Clean the CPU surface thoroughly with isopropyl alcohol to remove old thermal paste.
- Identify your CPU socket type (e.g., LGA1700, AM5).
3.2. Intel Socket Installation (LGA 1851/1700/1200/115x)
- Attach the Intel backplate to the rear of your motherboard, aligning the holes with the CPU socket mounting holes.
- Insert the appropriate Intel standoffs through the motherboard from the front, screwing them into the backplate.
- Attach the Intel mounting brackets to the pump block. Ensure they are securely fastened.
- Carefully place the pump block onto the CPU, aligning the holes on the mounting brackets with the standoffs.
- Secure the pump block by tightening the four thumb screws onto the standoffs in a diagonal pattern until snug. Do not overtighten.
- Mount the radiator to an available fan mount location in your case (e.g., top, front, or rear). The Mobius 120 Black fans are pre-installed on the radiator.
- Connect the pump's 3-pin or 4-pin power cable to the motherboard's AIO_PUMP or CPU_FAN header.
- Connect the fan cables (daisy-chained) to an available fan header on your motherboard (e.g., SYS_FAN).
- Use the provided tube clips to manage the coolant tubes for a cleaner build.
Figure 3.1: The MasterLiquid 240 Atmos Stealth AIO Liquid Cooler, showing the radiator with pre-installed fans and the pump block.
3.3. AMD Socket Installation (AM5/AM4)
- Remove the plastic retention clips from the stock AMD backplate, but keep the stock backplate in place.
- Screw the appropriate AMD standoffs into the stock AMD backplate's mounting holes.
- Attach the AMD mounting brackets to the pump block. Ensure they are securely fastened.
- Carefully place the pump block onto the CPU, aligning the holes on the mounting brackets with the standoffs.
- Secure the pump block by tightening the four thumb screws onto the standoffs in a diagonal pattern until snug. Do not overtighten.
- Mount the radiator to an available fan mount location in your case (e.g., top, front, or rear). The Mobius 120 Black fans are pre-installed on the radiator.
- Connect the pump's 3-pin or 4-pin power cable to the motherboard's AIO_PUMP or CPU_FAN header.
- Connect the fan cables (daisy-chained) to an available fan header on your motherboard (e.g., SYS_FAN).
- Use the provided tube clips to manage the coolant tubes for a cleaner build.
Figure 3.2: Side view of the MasterLiquid 240 Atmos Stealth, illustrating the radiator and pump block assembly.
4. Operating Instructions
Once installed, the MasterLiquid 240 Atmos Stealth operates automatically, regulating CPU temperature through its pump and fans.
- Initial Startup: After installation, close your computer case and reconnect the power cable. Power on your system. The pump and fans should begin operating.
- BIOS/UEFI Settings: Ensure your motherboard's BIOS/UEFI settings are configured to allow the CPU_FAN or AIO_PUMP header to run at full speed or be controlled by temperature. This ensures optimal cooling performance.
- Monitoring: Use system monitoring software (e.g., HWMonitor, CPU-Z) to verify CPU temperatures are within safe operating limits, especially under load.
- Pump Customization: The pump block top cover is transparent, removable, and can be customized with 3D-printed parts. Refer to Cooler Master's official resources for compatible designs and instructions.
Figure 4.1: Top-down view of the MasterLiquid 240 Atmos Stealth pump block, highlighting its design and customizable top cover.
5. Maintenance
Regular maintenance helps ensure optimal performance and longevity of your liquid cooler.
- Dust Removal: Periodically (every 3-6 months, or more frequently in dusty environments) use compressed air to clean dust from the radiator fins and fan blades. Ensure fans are not spinning rapidly during cleaning.
- Visual Inspection: Check the coolant tubes for any signs of kinks, leaks, or damage. Inspect the pump block and radiator for any unusual wear.
- Fan Inspection: Ensure fan blades are free of obstructions and spin freely.
- No Coolant Refill: This is a closed-loop AIO system and does not require coolant refills. Attempting to open the loop will void the warranty and may damage the unit.
Figure 5.1: Close-up view of a Mobius 120 Black fan, highlighting its design for efficient airflow and quiet operation.
6. Troubleshooting
If you encounter issues with your MasterLiquid 240 Atmos Stealth, refer to the following common problems and solutions.
| Problem | Possible Cause | Solution |
|---|---|---|
| High CPU Temperatures |
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| Unusual Noise from Cooler |
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| No Power to Cooler |
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If the problem persists after attempting these solutions, please contact Cooler Master customer support.
7. Specifications
| Model Number | MLX-D24M-A24PK-R1 |
| Product Dimensions (L x W x H) | 10.91" x 4.71" x 4.71" (277 x 119.6 x 119.6 mm) |
| Radiator Material | Aluminum |
| Fan Type | Mobius 120 Black (Pre-installed) |
| Fan Speed | 0 - 2400 RPM (PWM controlled) |
| Fan Airflow | 75.2 CFM (Max) |
| Fan Air Pressure | 3.63 mmH2O (Max) |
| Fan Noise Level | 30 dBA (Max) |
| Pump Design | Dual Chamber Pump |
| TDP Support | Up to 280W |
| Compatible Sockets | Intel: LGA 1851, LGA 1700, LGA 1200, LGA 1151, LGA 1150, LGA 1155, LGA 1156 AMD: AM5, AM4 |
| Power Connector Type | 4-Pin (for pump and fans) |
| Voltage | 12 Volts (DC) |
| Wattage | 280 watts |
8. Warranty and Support
Cooler Master products come with a limited warranty. For detailed warranty information, please visit the official Cooler Master website or refer to the warranty card included with your product.
For technical support, troubleshooting assistance, or to inquire about replacement parts, please contact Cooler Master customer service through their official website:
When contacting support, please have your product model number (MLX-D24M-A24PK-R1) and proof of purchase readily available.
