Testing the Heart of Liquid Cooling, Zhuomao Instruments' Complete CDU Qualification Line
As data centers accelerate toward high density and high power, liquid cooling has become the decisive thermal solution, and at its center sits the CDU, or Coolant Distribution Unit. The liquid cooling distribution unit is the indispensable equipment unit of the system, responsible for distributing coolant evenly, regulating temperature, controlling pressure and adapting flow, and its operating stability decides the cooling efficiency of servers and the life of the whole system.
As the core hub of the liquid cooling system, the data center cooling CDU integrates a circulation pump, liquid piping, heat exchangers, sensors and an intelligent control system. Its working logic is a closed loop: it receives low-temperature coolant from the external cold source, precisely regulates temperature, pressure and flow through its internal components, distributes it steadily to every server cooling terminal, recovers the heated coolant after it absorbs server heat, and sends it back to the external cold source for secondary cooling, supporting stable system operation.
Zhuomao Instruments focuses on AI compute cooling, with deep experience in CDU testing technology R&D and testing equipment manufacturing. It offers a complete, high-precision CDU testing solution that puts every stage under control, performance test, aging test, performance re-test, cleaning and drying, and vacuum nitrogen filling with pressure holding, providing full technical support for CDU quality control. This is the qualification line the AI GPU liquid cooling CDU market needs as volumes ramp.
Performance testing is the first gate every liquid cooling CDU supplier must pass. The system uses high-precision sensors and intelligent control to verify pressure control accuracy, temperature regulation range, leak detection sensitivity and power efficiency, simulating different operating conditions to confirm stability. Key specs: flow of 0 to 500 LPM with measurement accuracy of ±0.5% F.S., pressure range of 0 to 1000 kPa with accuracy of ±0.25% F.S., and temperature control from ambient to 60°C at ±1.5 to 3°C.
Aging testing validates the long-term reliability of the coolant distribution unit for liquid cooling. It reproduces the complex conditions a CDU faces across its full life cycle, including different ambient temperatures, system pressure fluctuations, coolant corrosion and sustained high-load operation, while continuously monitoring component states and performance parameters to catch performance degradation, material aging, seal failure and component wear before they cause field failures.
Internal cleanliness decides the life of every rack mounted liquid cooling CDU, which is what the flow channel cleaning and drying system exists for. High-efficiency cleaning and precise drying remove residual contaminants and moisture from the internal flow paths with full, dead-angle-free coverage, bringing the CDU to factory cleanliness and dryness. Cleaning modes cover forward flush, pulse and cavitation, with flow of 3 to 300 L/min, water pressure of 0.1 to 0.8 MPa, water temperature from ambient to 60°C and hot air drying from ambient to 80°C, achieving cleanliness of metal particles no larger than 50 μm and non-metal particles no larger than 150 μm.
The vacuum nitrogen filling and pressure holding system verifies the air-tightness and pressure stability of the server liquid cooling distribution unit to eliminate coolant leak risk. The system first evacuates the CDU to remove internal air and impurities, then fills it with dry nitrogen and holds a preset pressure, using long-term pressure monitoring to pinpoint leak points and leak volume before the unit ships. Key specs: nitrogen pressure of 5 to 900 kPa with control accuracy of ±1% F.S., pressure sensor accuracy of ±0.25% F.S., and an ultimate vacuum of -100 kPa.
For any OEM liquid cooling CDU manufacturer, the full set of Zhuomao testing equipment closes the quality loop: performance screening, aging validation, re-testing after aging, cleaning and drying to cleanliness standards, and vacuum nitrogen pressure holding for seal integrity. Every test step matches the actual needs of the CDU, balancing detection accuracy with throughput, and providing the solid assurance that keeps liquid cooling systems running efficiently and reliably through their entire service life.
Rigorous end-to-end testing workflows like these form the bedrock for dependable production-grade liquid-cooling solutions for AI compute facilities. AI shows no signs of slowing down—and your cooling infrastructure can't either. EXTRCOOL's liquid-cooling system merges CDUs, cold plates, manifolds, and piping into a single, fully unified platform. You can choose from our ready-to-deploy stock or work closely with our engineers to shape a configuration around your exact site requirements. The outcome: outstanding heat dissipation, lower electricity expenses, and a reduced environmental footprint—all substantiated by a proven track record at gigawatt-scale data centres around the world. For operations where even a second of downtime is unacceptable, EXTRCOOL is the partner you can rely on. Explore our complete product line or request a bespoke quote at: https://www.extrcool.com/
