Liquid cooling’s skills gap is in the field

Everyone talks about the hardware. CDUs, cold plates, manifolds, chips that need more cooling every generation. Far fewer people talk about the engineer with a filter rig and a test kit who decides whether any of it actually works.

That’s starting to change, and the clearest sign came from Vertiv this month.

I recruit critical cooling engineers. Liquid cooling needs good designers, and they’re not easy to find. But the gap that gets far less attention is on site: the people who prepare a system, commission it and keep it healthy. Vertiv has just bet on that, twice.

Vertiv has moved for the same capability twice in a year

In November 2025, Vertiv agreed to buy PurgeRite, a Houston business that provides mechanical flushing, purging and filtration for data centres and other mission-critical sites. The price was around $1bn in cash, with up to $250m more tied to 2026 performance. The deal completed in December.

On 24 September 2026 it agreed to buy King Environmental Services, founded in 2002 and headquartered near Dublin, with a second hub in Frankfurt. KES provides fluid-system preparation, flushing, filtration, water treatment, commissioning and thermal load testing for liquid cooling, as well as electrical load testing for critical power. Terms weren’t disclosed and the deal’s expected to close in the fourth quarter. It takes the same capability into Europe, the Middle East and Africa.

Vertiv already makes the hardware. In 2023 it bought CoolTera, a UK maker of CDUs, secondary fluid networks and manifolds, and it’s still buying hardware and design capability, including Strategic Thermal Labs and ThermoKey this year. But PurgeRite and KES are about the field: the people who make a new loop clean, air-free and chemically stable before handover, then keep it that way.

Vertiv paid around $1bn, roughly ten times PurgeRite’s expected 2026 earnings, for a flushing, purging and filtration business. That’s a clear signal of how much it values the capability.

Why liquid loops need specialist hands

An air-cooled hall is relatively forgiving. A liquid loop isn’t. If flow stops, there’s very little in the loop to buffer the heat.

Cold plates have microchannel passages far finer than anything in a building system. Debris left in new pipework, air trapped in the system, the wrong fluid chemistry or unbalanced flow can all cut heat transfer, damage components or hold up commissioning. When it announced the KES deal, Vertiv said contamination, trapped air, corrosion, improper chemistry and flow imbalance can reduce heat transfer, degrade equipment and create commissioning and operational risks.

The guidance reflects that. The Open Compute Project has published guidelines for pre-commission preparation of technology cooling system row manifold pipework, covering pressure testing, cleaning, flushing and filtration, with suspended solids monitored throughout. The CDUs stay isolated while the pipework is cleaned and flushed, and the racks are connected only once it’s clean. For UK engineers, one detail stands out. The first reference in that guideline is BSRIA’s BG29, and its minimum flushing velocities come from BG29’s tables.

The numbers are much tighter than on a building system. OCP recommends 5 micron final filtration and procedure water of RO or DI quality, and its guidance on water-based coolants calls for sampling weekly for the first month, monthly for a quarter and quarterly after that. ASHRAE advises that filters on the technology cooling loop should be 7 to 10 times finer than the smallest channel in the cold plate, and warns that the wrong water in a fine-pitch cold plate can cause plugging and corrosion. Once a system’s live, BSRIA’s BG50 covers water treatment for closed heating and cooling systems.

Resilience is harder too. Uptime Institute pointed out in April that redundant CDUs and manifolds need careful engineering and operation, because switching between units can cause turbulence effects that are difficult to model and predict.

The core of it is familiar: wet systems, water treatment and commissioning discipline. What’s different is the standard, and the fact that the loop runs right up to IT equipment worth a great deal.

The roles this creates

In practice, the demand lands in a handful of roles:

• Flushing and fluid management technicians, who clean, fill, purge and sample new loops.
• Pipefitters and welders who can work to the cleanliness standards stainless pipework demands, and pressure-test technicians.
• Water treatment specialists who understand closed-system chemistry, inhibitors, glycol mixes and OEM coolant specifications.
• Commissioning managers and engineers who can take CDUs and secondary loops through integrated systems testing, using liquid-cooled load banks or rack emulators.
• Water systems commissioning engineers, including flow measurement and balancing.
• Controls engineers who can bring CDU data into the BMS or DCIM and set sensible alarms.
• CDU manufacturers’ field service engineers, and service engineers who maintain pumps, filters and heat exchangers once the site is live.

Where these engineers come from

Very few engineers have five years of direct-to-chip experience in commercial data centres. It’s been used in supercomputing for more than a decade, but it’s only been deployed at scale in mainstream data centres recently. The good news is that most of the skills it needs are already out there.

The better pool is adjacent. The skills above already exist in:

• Pre-commission cleaning and water treatment of commercial pipework systems, the work covered by BSRIA’s BG29 and BG50.
• Chilled water and LTHW commissioning, including flow measurement and balancing.
• Oil and gas pre-commissioning, where flushing, pressure testing and chemical cleaning are routine.
• Process cooling in pharmaceuticals, food and manufacturing.
• Chilled water plant service.

A global survey of 161 data centre professionals by DCD Intelligence, reported by DCD on 18 September, points the same way. More than two-thirds of developers and operators said they’re staffed below what their operations need, with power and cooling among the hardest-hit areas. Fluid dynamics and power expertise were the biggest drivers of workforce expansion, with employers looking to power and water utilities and oil and gas to fill those roles. Uptime Institute’s larger 2026 global survey found 53% of operators struggling to find qualified candidates, up from 46% in 2025.

For most of these engineers, the technical gap is narrower than it looks. There’s new kit to learn, such as CDUs, rack manifolds, quick-disconnect couplings and in-rack leak detection, and tighter cleanliness standards. The bigger step is often the environment: permits, method statements, working around live IT and the pace of a commissioning programme. Both are teachable with a proper induction.

Keep it in proportion

Liquid cooling isn’t replacing air everywhere, and it’s worth saying so.

Uptime Institute’s 2025 cooling survey found 22% of organisations making some use of direct liquid cooling, the same as in 2024, while 75% used perimeter air cooling. In its 2024 survey, nearly half of those using direct liquid cooling said it cooled less than 10% of their racks. Uptime’s view in April 2026 was that direct liquid cooling is unlikely to go mainstream in the next three years, and that most operators won’t deploy it at scale for their mission-critical applications.

So this isn’t a case for every cooling business building a liquid cooling team tomorrow. The demand is concentrated in AI and high-density builds, and that’s where the skills gap will bite first. It’s also where the money and the programme pressure are.

If you’re hiring

• Hire for fluids, commissioning and controls, not for “liquid cooling experience”.
• Write the job spec around the tasks: flushing, sampling, balancing, CDU commissioning, load testing. Engineers from adjacent sectors will recognise themselves in that.
• Budget for a proper induction into the data centre environment.
• Be clear about what the role involves day to day, including travel and on-call, so the right people apply.
• Start early. If a liquid-cooled hall is due to commission next year, now’s the time to line up the people who’ll prepare and commission it.

If you’re an engineer

If you’ve spent years commissioning chilled water, cleaning and treating closed systems, balancing wet systems or servicing chilled water plant, you’re closer to data centre liquid cooling than the job adverts suggest.

The things worth having on your CV are specific. Flushing and cleaning procedures you’ve run. Fluid sampling and chemistry. Balancing. Commissioning to design flow and temperature. Any controls work. Those are what a good hiring manager will ask about.

---

I recruit in critical cooling, for cooling businesses and data centre operators in the UK and Europe. If you’re planning a liquid-cooled build, or looking for engineers who can commission and service one, I’m happy to talk through what we’re seeing.

---

Sources: Vertiv, Vertiv announces intent to acquire PurgeRite (Nov 2025); Vertiv, Vertiv announces agreement to acquire King Environmental Services (Sept 2026); Vertiv, Vertiv acquisition of CoolTera Ltd. boosts liquid cooling portfolio (Dec 2023); Open Compute Project, Guidelines for pre-commission preparation of technology cooling system (TCS) row manifolds (Mar 2025); BSRIA, BG 29/2021 Pre-commission cleaning of pipework systems (2021); BSRIA, BG 50/2021 Water treatment for closed heating and cooling systems (Nov 2021); ASHRAE TC 9.9, Water-cooled servers: common designs, components and processes (2019); Uptime Institute, Cooling Systems Survey 2025 (July 2025); Uptime Institute, Liquid cooling will not outgrow its high-density niche (Apr 2026); Uptime Institute, Global Data Center Survey 2026 (July 2026); DCD, DCD Intelligence: Data center expansion is outpacing talent (Sept 2026).