Install the NVSwitch cold plate module

Follow instructions in this section to install the NVSwitch cold plate module. The procedure must be executed by a trained technician.

About this task

Attention

• Read Installation Guidelines and Safety inspection checklist to ensure that you work safely.
• Touch the static-protective package that contains the component to any unpainted metal surface on the server; then, remove it from the package and place it on a static-protective surface.
• Two people and one lifting device on site that can support up to 400 lb (181 kg) are required to perform this procedure. If you do not already have a lifting device available, Lenovo offers the Genie Lift GL-8 material lift that can be purchased at Data Center Solution Configurator. Make sure to include the Foot-release brake and the Load Platform when ordering the Genie Lift GL-8 material lift.
• A torque screwdriver is available for request if you do not have one at hand.

Note

Make sure you have the required tools listed below available to properly replace the component:

• Torx T15 head screwdriver
• Phillips #1 head screwdriver
• Phillips #2 head screwdriver
• Flat head screwdriver
• Alcohol cleaning pad
• NVSwitch PCM Kit
• NVSwitch putty pad Kit

Important

Putty pad/phase change material (PCM) replacement guidelines

• Before replacing the putty pad/PCM, gently clean the hardware surface with an alcohol cleaning pad.
• Hold the putty pad/PCM carefully to avoid deformation. Make sure no screw hole or opening is blocked by the putty pad/PCM.
• Do not use expired putty pad/PCM. Check the expiry date on putty pad/PCM package. If the putty pads/PCM are expired, acquire new ones to properly replace them.

The following illustration shows the GPU numbering and corresponding slot numbering in XCC.

Figure 1. GPU numbering

The following illustration shows the components for NVSwitch cold plate module.

Figure 2. NVSwitch cold plate module components identification

Table 1. NVSwitch cold plate module components

1 NVSwitch cold plate torque label	2 Leakage sensor module
3 Hose tie	4 Handle
5 NVSwitch cold plate	6 NVSwitch slot number label
7 Manifold

Procedure

1. Make sure the GPU complex is installed in the chassis.
2. Replace the Phase Change Material (PCM) and putty pads on the cold plates.
   1. Remove the liner from one side of the pad. Align the PCM with the marking (1) on the bottom of the cold plate, and place it onto the cold plate; then, apply finger pressure across the entire surface area of the PCM to remove any trapped air and allow 1-2 minutes dwell time until it is firmly attached. Carefully remove the remaining top liner.
   2. Remove the liner from one side of the pad. Align the putty pad with the marking (2) on the bottom of the cold plate, and attach it to the cold plate and apply light finger pressure across the entire surface area of the pad to ensure adhesion. Carefully remove the remaining top liner.
   3. Repeat to replace the PCM and putty pads on the four cold plates.
   Attention

   • PCM cannot be reused. PCM must be replaced with new ones every time the water loop is removed.

   • After PCM is replaced, there is an expected short duration of throttling before the GPU returns to normal operation. This is due to the PCM requiring a break-in period after being replaced.

   • After replacing the GPU PCM and putty pads, servicers must perform the H100/H200 GPU PCM TIM melting procedure to monitor the GPU until the PCM Thermal Interface Material (TIM) has melted. See PCM TIM Melt Procedure for Neptune Water Cooled Servers with Nvidia H100 H200 GPUs (trained technicians only).

   Figure 3. PCM and putty pads application
   
   
3. Install the NVSwitch cold plate module.
   1. Lift the NVSwitch cold plate module by the handles; then, align the cold plates with the NVSwitches on the GPU baseboard, and gently place it onto the NVSwitches.
   2. Adjust the cold plates until they are securely seated in the NVSwitch sockets.
   Figure 4. Installing the NVSwitch cold plate module
   
   
4. Follow the screw sequence specified on the cold plate label, and repeat to fully tighten the sixteen Torx T15 screws with a torque screwdriver set to the proper torque.
   1. Set the torque screwdriver to 0.57-0.61 newton-meter, 5-5.4 pound-inch.
   2. Fasten the screws 720 degrees following the screw installation sequence: → → →
      Note

      Make sure to follow screw installation sequence to prevent cold plate tilting.
   3. Repeat until all screws on the four cold plates are fully tightened.
   Figure 5. Repeat to fully tighten all the screws
   
   

   Figure 6. Installing the NVSwitch cold plates
   
   
5. The following illustration shows the hose holder location.
   Figure 7. Hose holder location
   
   
6. Place the NVSwitch cold plate module hoses on (1) hose holder A.
   Important

   • Check the guiding labels on the hoses and hose holders before installation.

   Figure 8. Placing the hoses
   
   

   1 Hose holder A

7. Align the hose holder B/C with the two screw holes on hose holder A; then, fasten the two captive screws (PH1, 2 x M3, 0.5 newton-meters, 4.3 inch-pounds) to secure hose holder B/C on top of hose holder A. Repeat to install hose holder B/C on the other side.
   Figure 9. Installing hose holder B/C
   
   
8. Align the hose guide with the screw hole on the NVSwitch manifold and the two screw holes on the chassis; then, fasten the three M3 screws (PH2, 3 x M3, 0.5 newton-meters, 4.3 inch-pounds) to secure the hose guide. Repeat to install the hose guide on the other side.
   Figure 10. Installing the hose guides
   
   
9. If you are installing the NVSwitch cold plate module after installing a new GPU complex, skip the following two steps and proceed to install the front H100/H200 GPU cold plate module. See Install the front H100/H200 GPU cold plate module.
10. If front and rear GPU cold plate modules are installed, place the hoses and cables on the hose guides, and secure them with the hose ties. See Fan control board cable routing and Leakage sensor module cable routing.
    Figure 11. Placing the hoses and cables on the hose guides
    
    
11. If front and rear GPU cold plate modules are installed, reinstall the hoses to their corresponding places on hose holder B/C; then, reinstall the rear fan cage support bracket. Ensure the labels on the hoses match with the markings on the hose holders.
12. Install the rear fan cage support bracket.
    1. Align the rear fan cage support bracket with the corresponding screw holes; then, install the rear fan cage support bracket on top of hose holder B/C as illustrated.
    2. Fasten the four M3 screws (PH2, 4 x M3, 0.5 newton-meters, 4.3 inch-pounds) to secure the rear fan cage support bracket to the fan cage.
    3. Fasten the eight M3 screws (PH2, 8 x M3, 0.5 newton-meters, 4.3 inch-pounds) to secure the rear fan cage support bracket to the chassis.
       Figure 12. Installing the rear fan cage support bracket