As power densities rise and AI workloads reshape infrastructure demands, Immersion Cooling is becoming a cornerstone of next-generation Data Centre Cooling strategies. But long-term performance, reliability, and uptime depend on disciplined preparation and fluid management.

This practical checklist, based on Castrol’s official deployment guidance, provides a clear framework for installing, operating, and maintaining Castrol ON Immersion Cooling Fluids in modern data centre environments.

Why a Checklist Matters for Immersion Cooling

Immersion cooling systems place IT hardware directly into dielectric fluid. Any oversight in preparation, material compatibility, cleanliness, or handling can lead to:

• Fluid contamination

• Reduced cooling efficiency

• Hardware degradation

• Dielectric failure

• Unexpected downtime

A structured checklist ensures your immersion cooling deployment is robust, repeatable, and future-proof.

Immersion Cooling Fluid Preparations Before Deployment

1. Material Compatibility

Before introducing Castrol ON into your system, verify that all submerged components are compatible with immersion cooling:

• Servers and IT hardware

• Cables and connectors

• Thermal interface materials (TIMs)

• Gaskets, seals, and elastomers

2. Installation Compliance

Your immersion cooling infrastructure must be installed exactly as specified by the system manufacturer:

• Immersion tank installed per manufacturer’s manual

• Electrical connections meet regulatory standards

• Plumbing connections follow approved specifications

• Installation approved by certified specialists or the facilities team

This ensures regulatory compliance and operational safety.

3. IT Equipment Preparation

Before submersion:

• Use only cables and connectors tested for submerged operation

• Remove any non-immersion-rated materials

• Replace incompatible thermal pastes

• Confirm all components are immersion-ready

System Cleanliness and Fluid Handling

4. System Cleanliness

Contamination is one of the most common causes of immersion cooling issues.

Before filling:

• Ensure tanks, CDU (Coolant Distribution Unit), and HX (Heat Exchanger) are thoroughly cleaned

• Remove any residual fluids or manufacturing oils

• Flush all pipework according to manufacturer guidelines

• Verify all hoses and containers are debris-free

5. Immersion Cooling Fluid Storage and Handling

Store Castrol ON immersion cooling fluids in a:

• Clean

• Temperature-controlled

• Contamination-free environment

Ensure fluid-handling equipment is clean and suitable for dielectric fluids.

Fluid Sampling and Quality Control

6. Immersion Cooling Fluid Sampling

Take representative fluid samples at two critical stages:

1. After filling the tank, but before submerging the  IT equipment

2. After the IT equipment has been submerged

These samples help identify contamination, particulate matter, or unexpected chemical reactions before problems escalate.

Step-by-Step Deployment Checklist

Pre-Filling Immersion Cooling Fluid Tank and Equipment Check

• Tank is completely empty

• No residual fluids, oils, or particles

• Tank, CDU, and HX flushed

• No corrosion or mechanical damage

• All materials verified as compatible with Castrol ON

During the Filling Process

• Fill slowly to prevent air entrapment

• Take a fluid sample before IT submersion

• Allow suspended particles to settle or be filtered

• Confirm all IT components are in optimal condition

Submersion of IT Equipment

• Remove incompatible thermal pastes

• Verify cables and connectors are immersion-rated

• Submerge hardware according to system manufacturer guidelines

• Take post-submersion fluid sample

• Inspect for discoloration or foreign particles

Post-Installation and Operational Checks

Immersion Cooling Fluid Maintenance

• Implement routine fluid sampling

• Monitor for contamination or degradation

• Follow recommended fluid replacement intervals

System Performance Monitoring

• Monitor thermal performance

• Track fluid flow rates

• Watch for rising temperatures or reduced cooling efficiency

Component Wear and Tear

• Inspect submerged components for corrosion or degradation

• Maintain CDU, piping, and filtration systems

• Schedule periodic preventative maintenance

Common Issues to Avoid

Avoid these common deployment mistakes:

• Using thermal paste not rated for immersion cooling

• Submerging untested cables or connectors

• Filling unclean tanks or CDUs

• Mixing Castrol ON with competitor fluids

• Using the wrong product grade

• Topping up without lab compatibility testing

Always verify product labels, batch numbers, and delivery notes before filling.

Why Castrol ON for Data Centre Cooling?

Castrol ON single-phase immersion cooling fluids are engineered specifically for high-density digital infrastructure:

• Outstanding dielectric performance

• Excellent thermal conductivity

• Long fluid life

• Proven hardware compatibility

• Global technical support

They are trusted in hyperscale, AI, blockchain, and HPC deployments worldwide.

Final Checklist for Immersion Cooling Success

Before commissioning your system, confirm:

✔  All materials are immersion-compatible
✔  Installation meets manufacturer and regulatory standards
✔  IT equipment is immersion-ready
✔  Tank and CDU are fully cleaned
✔  Fluid is sampled before and after submersion
✔  System performance is continuously monitored
✔  Preventative maintenance is scheduled

Building a Reliable Immersion Cooling Operation

Immersion cooling is transforming data centre cooling by unlocking higher compute density, improved energy efficiency, and reduced carbon impact. But success depends on disciplined processes and proven fluids.

By following this checklist and deploying Castrol ON Immersion Cooling, operators can achieve:

• Higher uptime

• Lower thermal risk

• Extended hardware life

• Improved energy efficiency

• Future-ready cooling infrastructure

Need Technical Support?

For fluid compatibility testing, deployment support, safety or technical documentation, contact your Kernow Oils representative or email:

info@kernow-oils.co.uk