Liquid-Cooled Systems Deployment

Overview 

The SN6600-LD, SN6810-LD and SN6800-LD liquid-cooling systems feature parallel cooling loops operating concurrently. The below curves apply to PG25 at 45°C (see (1.0) Specifications). As the systems have two parallel inlet/outlet ports, the flow rate at the operating condition is half the total switch liquid flow rate.

Deployment

Inserting the Switch Module (Liquid System Related)

The switch modules are pre-filled with nitrogen gas in the cooling system, pressurized to at least 1 psi. If the pressure is below 1 psi, perform a "Pressure Hold": refill to 50 psi with N2, wait 12 hours, and verify that the pressure remains above 48 psi to pass. Positive nitrogen pressure prevents humidity or dust ingress.

Note: The switch modules feature integrated Universal Quick Disconnect (UQD8) connectors that protrude directly from the chassis. They are designed to blind-mate directly into the MGX rack manifold cooling loop upon insertion. External extension hoses are not required or used for deployment.

Before inserting the switch module into the rack, the protective nitrogen gas must be completely purged from all internal cooling loops using the open-ended purge hose provided in the maintenance kit.

Purging Procedure:

1. Identify the number of UQDs pairs for your specific switch model (see table below), each pair is inlet and outlet of a cooling loop.

2. For each pair of UQDs, connect the open-ended maintenance purge hose to the outlet UQD8 connector to automatically expel the gas.

3. Disconnect the purge hose once the gas is fully released from the loop.

4. Repeat for all remaining pairs on the switch before proceeding with final insertion.

Liquid-Cooling System Related Actions 

Pressure Check of Nitrogen-Filled Components

Purpose:

• Confirm that cold plate assemblies, switch trays, and manifolds retain supplier-filled N2 pressure, ensuring no leaks during transit.

Required Hardware:

• Digital pressure gauge (0–2.1 bar or 0–3.4 bar), data logging.

Process

• Scan the QR code, log pressure

• Release the internal pressure

• Cycle time: <1 minute

Pass/Fail Criteria

• Must retain ≥1 psi.

• If the pressure is lower than 1 psi, please perform a "Pressure Hold" test as follows:

  • Refill to 50 psi with N2

  • Wait 12 hours

  • Recheck the pressure. If the pressure is above 48 psi, the unit has passed the test.

• Failures are returned to the supplier.

PG25 Fill

Purpose:

• To fill assemblies (both individual components and full racks) with 25% propylene glycol, and 75% water solution, ensuring complete fluid coverage and air removal for optimal thermal performance.

Required Hardware:

• For vacuum fill: Vacuum pump, liquid trap

• For positive pressure fill: Fill pump

• 25-micron filter on the supply side (for both the component and the rack)

Process

• Vacuum Fill:

  • Pull vacuum on the assembly from the outlet quick disconnect (QD).

  • Fill the fluid from the inlet QD.

  • Stop filling when the fluid enters the liquid trap.

  • Vacuum specification: 5 kPa or less.

• Positive Pressure Fill:

  • Use a fill pump to introduce coolant.

  • Circulate the fluid back into the reservoir briefly to ensure no bubbles remain.

Pass/Fail Criteria

•  Fluid reservoir weight can optionally be measured before and after filling as a quality check.

Caveats: 

• If using a positive pressure pump with circulation, ensure a 25-micron filter is installed on the supply side.

• If the assembly is complex with multiple fluidic elevations or high points, vacuum filling is preferred.

• Expected Cycle Time: 2–3 minutes.

Last updated: July 02, 2026