I. Background: The AI Computing Power Explosion Makes Liquid Cooling a Necessity

In 2025, global AI server output value exceeded USD 400 billion, up 45% year on year. The NVIDIA Blackwell GB200 has a single-GPU power consumption of 1200W, and the power consumption of a complete rack exceeds 120kW—traditional air cooling can no longer meet the heat dissipation requirements.

The penetration rate of liquid cooling solutions climbed rapidly from 14% in 2024 to over 30% in 2026. Cold plate liquid cooling has become the mainstream choice (with a market share of approximately 65%), while immersion liquid cooling is being deployed at an accelerating pace in high-density scenarios.

Key components involved in liquid cooling systems —Cold Plate, CDU (Coolant Distribution Unit), Manifold, Quick Connect, Cooling LinesEvery component's sealing reliability directly determines the safety and service life of the data center.

II. Core Pain Points of Liquid Cooling Sealing

Pain point 1Coolant Leak = Catastrophic Disaster for IT Equipment

The internal circulation of a liquid cooling system uses deionized water, glycol solution, or fluorinated liquid. Once the seal fails:

Conductive coolant leak→ Server short circuit → A single failure can cause losses of millions of yuan
Microchannel leaks in liquid cooling plates (at the 0.1 mL/min level) are difficult to detect with traditional water immersion testing.
A financial data center experienced a server short circuit caused by coolant degradation, resulting in a single-incident loss exceeding 3 million yuan.

Industry requirement: The CDU sealing test threshold must reach10⁻⁵ ~ 10⁻⁷ mbar·L/sLevel.

Pain Point 2Many welds/joints, hidden leak points

A single liquid cooling system contains dozens of potential leak points:

Components	Typical leak points	Quantity/unit
Cold plate	Brazed/friction stir weld seams, inlet and outlet joints	2 to 6 locations
CDU	Heat exchanger welds, pump seals, valve bodies, sensor interfaces	20+ locations
Manifold	Distributor weld points, quick connectors	10 to 30 locations
Quick connector	O-ring seal, plug-in end face	1 pair per GPU
Cooling line	Pipe fittings and elbow welding	Dozens of locations

Every joint, weld seam, and sealing ring is a potential leak path.

Pain point 3Compatibility Challenges of Fluorinated Fluids/Coolants with Sealing Materials

Some ABS plastic seals exhibited swelling and deformation after being immersed in fluorinated fluid for 6 months.
Long-term coolant circulation may produce acidic degradation products that corrode sealing surfaces.
Accelerated aging of rubber seals under high-temperature conditions (130°C aging test)

Pain point 4Traditional leak detection methods are falling short.

Method	Limitations
Water immersion bubble test	Low sensitivity, unable to detect微小 leaks; risk of water residue
Pressure decay method	Temperature-sensitive; insufficient detection accuracy for large-volume CDUs; unable to locate leak points
Vacuum method	Not suitable for assemblies with precision electronic components or soft plastic housings.

Pain point 5The conflict between production line takt time and testing accuracy

Mass production requires fast, highly reliable leak detection solutions, while traditional methods are either slow, inaccurate, or only capable of qualitative assessment without locating leaks. Cold plate manufacturers require 100% inline leak detection, but the inspection time available for each product on the production line is limited.

III. PLUS Solutions: Full Coverage from Air Sealing Test to Hydrogen Detection

PLUS (Guangzhou) Intelligent Technology has focused on the sealing test field for over 8 years and is a national high-tech enterprise (+ CE certification + ISO certification). Its product line covers the full chain from conventional air tightness testing to high-precision tracer gas leak detection, fully matching the sealing test requirements of every stage of AI server liquid cooling systems.

Option 1Cold plate / liquid cooling plate air tightness testing

Recommended equipment: X530 High-Precision Differential Pressure Leak Detector / D530 High-Precision Direct Pressure Leak Detector

24-bit high-precision sampling— Sensitively captures minute pressure changes, leaving no micro-leak undetected
Differential pressure range ±500~±5000 Pa— Compatible with different cold plate design requirements
99 parameter sets— Rapid changeover between multiple cold plate models, supporting flexible line changeovers
8 IN / 8 OUT IO interface + RS232/TCP/IP— Seamless integration with automated production lines for 100% inline leak testing
Optional electrically controlled pressure regulating valve, automatically adjusts test pressure

Suitable for:Copper alloy cold plate, aluminum alloy cold plate, microchannel cold plate, vacuum brazed cold plate, friction stir welded cold plate

X530 High-Precision Differential Pressure Leak Detector

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Customer value:Before leaving the factory, 100% air tightness testing is performed on cold plates to ensure no micropores in welds and no leaks at joints, preventing coolant from seeping into server chassis.

Option 2CDU (Coolant Distribution Unit) Finished Product Sealing Verification

Recommended equipment: PLUS Nitrogen-Hydrogen Tracer Leak Detector / P520 High-Precision Flow Tester

P520 High-Precision Flow Tester

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The CDU is the "heart" of a liquid cooling system, containing dozens of potential leak points such as heat exchangers, pumps, valves, and sensor interfaces.Require full-machine verification after all components are assembled.。

Option A — Nitrogen-Hydrogen Tracer Leak Detection (Recommended)

Use a 5% H₂ + 95% N₂ gas mixture (forming gas, safe and non-flammable)
After filling the CDU system, scan along the welds, joints, and sealing surfaces with a sniffer probe.
Precisely locate the leak point, on-site repair + retest
Sensitivity up to 10⁻⁵ ~ 10⁻⁷ mbar·L/s, meeting industry standards
Not affected by temperature/humidity,Dry, non-corrosive, residue-free

Option B — Quantitative Flow Testing

P520 flow tester accuracy ±0.8% of reading ±0.2% of full scale
Selection range: 0.5~200 sccm / 500 sccm / 1~1500 SLPM
Quantitative leak rate data output, capable of integrating with MES systems

Customer value:It not only provides a qualitative judgment of "leaking or not leaking" but also delivers quantitative data on "how much is leaking." At the same time, tracer gas sniffing precisely locates the leak point, greatly improving the first-time repair pass rate.

Option 3Quick connector sealing life test

Recommended equipment: P530 Flow Tester

Quick connectors are required to maintain zero leakage after thousands of insertion and removal cycles. Utilizing the P530's999 sets of extra-large parameter groups, yes:

Set multiple test parameter groups for before/after insertion and removal.
Record the leak rate data for each test.
Track the sealing performance decay curve
Set a fail threshold for automatic alarm

Option 4Immersion liquid cooling tank / sealed enclosure leak detection

Recommended equipment: MT100 multi-station tester / X730 integrated leak detector

MT100 supports 1 to 4 stations, with automatic pressure regulation (up to 4 MPa)
X730 Built-in Sealing Fixture + Dynamic Pressure Curve + 20,000 Historical Records
Dedicated Solution for Sealing Testing of Large-Volume Cavities

Plan 5Cooling line/connector sealing test

Recommended equipment: D530 direct pressure leak detector

Quickly seal both ends of the pipeline, then pressurize with air and monitor the pressure decay.
Paired with PLUS's ownQuick sealing connector(external card sleeve type / internal expansion jaw type / pneumatic internal expansion type), compatible with different pipe diameters
The single-piece test cycle can be controlled within 15–30 seconds, making it suitable for high-volume production lines.

IV. Hydrogen Detection: PLUS's Core Differentiating Capability

PLUS has deep expertise in hydrogen detection:

Year	Milestones
2020	Launch hydrogen leak testing equipment
2021	Hydrogen fuel cell bipolar plate sealing test equipment delivered
2024	Launch helium mass spectrometer leak detection equipment
2025	Launch hydrogen mass spectrometer testing equipment

In liquid cooling scenarios,Hydrogen-nitrogen tracer leak detectionCompared with helium leak testing, it offers three core advantages:

Cost advantage— 5% H₂ + 95% N₂ gas mixture costs far less than helium, eliminating the need for a helium supply chain
Safe and reliable- 5% hydrogen is well below the lower flammability limit (4% LFL), making it safe and non-flammable
Comparable accuracy— Hydrogen has the smallest molecular weight, and its tracer sensitivity is no less than that of helium.

PLUS is one of the few companies that simultaneously mastersAir pressure leak detection, flow leak detection, nitrogen-hydrogen tracer leak detection, helium mass spectrometer leak detection, hydrogen mass spectrometer leak detectionDomestic manufacturers of five technology routes.

V. Why Choose PLUS

Since 2018, PLUS has been deeply engaged in sealing testing, serving multiple industries including new energy, automotive, and consumer electronics, and has extended its proven capabilities to sealing test applications for AI server liquid cooling systems.

8 years of focus on sealing tests

From 2018 to the present, we have focused on one thing only—sealing test.
We have accumulated experience with hundreds of solutions in the new energy, automotive, and consumer electronics industries.
Liquid cooling circuit testing is simply an extension of our existing capabilities.

Full product line, one-stop procurement

From differential pressure leak detection to direct pressure leak detection, from flow leak detection to tracer gas leak detection.
From helium mass spectrometry to hydrogen mass spectrometry — customers don't need to look for multiple suppliers; PLUS covers it all.

Liquid cooling case studies

Radiator Sealing and Vacuum Filling System: Integrated Hydrogen-Nitrogen Sealing Test + Vacuum Filling
Hydrogen fuel cell plate sealing test: 100% inspection of bipolar plate sealing performance, meeting the highest standards of the hydrogen energy industry
Cooling line sealing test: air tightness testing for power battery thermal management liquid cooling lines
Water Pump Helium Testing Equipment: Helium Testing for Thermal Management Systems

Complete qualifications

High-Tech Enterprise(Recognized by the Ministry of Science and Technology of China)
CE Certification(Certificate No.: M.2024.206.C99088, LVD+EMC)
ISO certification(Chinese and English bilingual version)
15 utility model patents + 3 software copyrights

Custom-engineered solutions + full-line delivery

From standalone units to complete lines, from manual to fully automated
Supports barcode scanning for MES binding, data traceability, fixture control, and automatic sorting
Multiple complete-line projects delivered (3 test systems + fixtures + data acquisition)

Customer Type	Application Scenarios
Cold plate manufacturer	100% air tightness testing at the factory, integrated into mass production lines
CDU assembly plant	Complete machine helium leak testing / nitrogen-hydrogen tracer testing, precisely locating leak points
Liquid cooling system integrator	Incoming inspection of components + full-system verification
Server OEM	Liquid cooling plate / quick connector incoming material sealing verification
Data center operators	CDU pre-installation acceptance test, in-service leak inspection
Immersion liquid cooling manufacturers	Sealed enclosure air tightness + pipeline sealing test

AI Server Liquid Cooling System Sealing Test: Pain Points and Solutions