BOYD RAA32-10U21 CDU Refill SOP

This article describes the standard operating procedure for refilling coolant, venting trapped air, and verifying dual-pump redundancy on a BOYD RAA32-10U21 CDU, ensuring the liquid cooling loop runs reliably at stable pressure.

Overview

To refill and commission the BOYD RAA32-10U21 CDU, follow these steps:

1. Connect the refill and exhaust hoses — Attach hoses to the CDU’s COOLANT FILLING and EXHAUST PORT connectors, with both hose ends submerged in an external coolant tank.
2. Run the refill pump — Draw coolant from the external tank into the system and bleed air from the loop.
3. Start the CDU and check pressure — Confirm the secondary loop return pressure (P2) reaches the acceptance threshold.
4. Verify pump redundancy — Trigger a forced pump switch to confirm dual-pump failover works correctly.

Note: Residual pressure may remain in the EXHAUST PORT after the CDU has been running. Always position the hose first, then make the connection, to avoid gas release or coolant spray.

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Equipment List

Item	Qty
G4520G6 server	1
BOYD RAA32-10U21 CDU	1
External coolant storage tank	1
Refill hoses (inlet + exhaust)	2
Cleaning cloth	1+
Personal Protective Equipment (PPE)	as required

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Safety Precautions

Residual pressure at the EXHAUST PORT

The EXHAUST PORT on the rear of the CDU may retain residual system pressure.

To avoid gas release or coolant spray when connecting:

Position the hose first, then connect the quick connector — never the other way around.

Hose kick-out during refill

Fluid impact during refill can cause the hose to jump out of the storage container.

Pack the opening of the external tank tightly with a cleaning cloth to keep the hose seated.

System configuration

A complete secondary liquid cooling loop is established between the server and the CDU, forming a closed-circuit cycle.

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Refill Procedure

Step 1 — Confirm Power

Connect the CDU to power and confirm the supply is normal.

Step 2 — Connect the Exhaust Hose

Remove the black protective cap from the rear EXHAUST PORT and attach the first hose using its quick connector. Keep the hose end submerged in the external coolant tank to prevent spillage.

Step 3 — Connect the Refill Hose

Remove the black protective cap from the rear COOLANT FILLING port and attach the second hose using its quick connector. Keep this hose end submerged in the tank as well.

Step 4 — Confirm Port Mapping

Port	Description
INT	System refill port (COOLANT FILLING)
EXT	System exhaust port (EXHAUST PORT)

Once running, the system actively draws coolant from the external tank to fill the loop.

Step 5 — Start the Refill Pump

Turn on the Refill Pump from the CDU touch panel.

Step 6 — Bleed Air

Watch the EXHAUST PORT for air bubbles. Once no bubbles remain, release the quick connector lock without fully disconnecting it.

Step 7 — Complete Refilling

The refill pump stops automatically once filling is complete.

If coolant was already present in the loop:

• Bleeding typically takes 3–5 minutes
• Confirm all air has been fully expelled before proceeding

Step 8 — Start the CDU

Power on the CDU.

Step 9 — Check Return Pressure

Monitor Return Pressure (P2) on the system status screen.

Acceptance Criteria

• P2 ≥ 130 kPa

Notes

A transient pressure dip may appear within 1–2 minutes of startup. Wait for the reading to stabilize before making a final judgment.

Step 10 — If Pressure Is Insufficient

If P2 does not reach 130 kPa:

1. Turn off the CDU
2. Turn on the Refill Pump
3. Wait for the automatic refill to finish
4. Return to Step 8

Step 11 — Verify Pump Redundancy

Trigger Force Pump Switch and confirm the dual-pump failover behaves correctly.

Step 12 — Power Off

Turn off the CDU.

Step 13 — Disconnect Hoses

Remove the hoses from both the EXHAUST PORT and COOLANT FILLING ports. Wipe up any coolant that leaks out during disconnection immediately.

Step 14 — Recover Residual Coolant

Raise the disconnected hoses so gravity drains any remaining coolant back into the tank. Performing this step with two people is recommended.

Step 15 — Final Check

Confirm:

• Hoses have fully finished dripping
• No coolant remains on site
• The unit is restored to its original state

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Acceptance Checklist

Check Item	Done
Refill completed	☐
Air bleeding completed	☐
P2 ≥ 130 kPa	☐
Force Pump Switch verified	☐
Residual coolant cleaned up	☐
Site restored	☐

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Conclusion

Once all steps above are complete, the BOYD RAA32-10U21 CDU liquid cooling loop has been refilled, bled of air, and functionally verified, and is ready for normal operation.