Imagine you are not standing in the boiler room of a single-family house, but in the heart of a data center. Dozens of racks, packed with servers, are blinking at you. There is a hum, a rush – and everything depends on a single, invisible medium: reliable cooling.
Because without constant temperatures, the systems overheat in no time. And when that happens, it’s not just a heater that stops, but entire companies, banks, or government agencies. That’s exactly why cooling water in the data center is a topic that is becoming increasingly important for us HVAC professionals – and this is where VDI 6044 comes into play.

VDI 6044 – the guideline for water quality in cooling systems

VDI 6044 bears the title “Prevention of damage in chilled water and cooling circuits” and is the key guideline when it comes to planning, operating, and maintaining cooling circuits – for example, in data centers.
Why? Because the requirements in a data center are different from those in a classic heating system:

High availability: Downtime is not an option – cooling must run 24/7/365.
Constant conditions: Even the smallest deviations in temperature or water quality can have an impact.
Large volumes: Cooling water systems in data centers often move thousands of liters – mistakes have correspondingly multiplied effects.

VDI 6044 therefore sets clear requirements for the cooling water and specifies how to avoid corrosion, deposits, and biological contamination.

The key requirements of VDI 6044

So that you as a professional immediately know what matters in everyday practice, here are the most important points:

Corrosion protection
Metal components in the cooling circuit must not be attacked by unsuitable water chemistry. There are specific requirements for conductivity, pH value, and inhibitors.
Deposit prevention
Lime, sludge, or magnetite have no place in cooling water. Even the smallest deposits can block heat exchangers and drastically reduce cooling performance.
Biological stability
Bacteria and biofilms can form in cooling water – with fatal consequences: from clogged pipes to hygiene problems. The guideline therefore requires regular monitoring and appropriate countermeasures.
Monitoring & documentation
Similar to heating systems (VDI 2035, ÖNORM H 5195-1), the following applies: It is not enough to treat the water just once. Ongoing monitoring is mandatory, including measurement protocols.

WaterBoy measuring case

The UWS WaterBoy measuring case contains everything the HVAC specialist needs to measure data in accordance with the VDI 2035, ÖNORM H 5195-1 and SWKI BT 102-01 standards in two L-BOXXES.
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What does this mean for you as an HVAC professional?

Many colleagues know VDI 2035 inside and out when it comes to heating water. But in the cooling water of data centers, the same principles apply – just at a much higher level.
Imagine: A lime deposit of just a few tenths of a millimeter can reduce the cooling performance in the server rack so much that processors throttle or systems shut down. An invisibly thin biofilm can act like an insulating layer. And corrosion in the pipe? The ticking time bomb in the background.

With VDI 6044 in hand, the rules of the game are clear:

Which water quality must be maintained.
How to properly prepare the system for commissioning.
Which checks during ongoing operation are mandatory.

This ensures that the data center runs stably in the long term – and that you as a professional deliver exactly what operators expect: safety, availability, reliability.

Heaty Ferriline No. 2

Complete unit for professional bypass treatment, sludge and magnetite filtration in the hot water area incl. MAGella twister
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Typical practical scenarios

New construction of a data center
You are involved in building a new server location. VDI 6044 gives you the checklist to ensure the cooling water is right from day one – no discussions with the operator, no nasty surprises.
Expansion of an existing system
Old and new circuits meet. Different materials, different stresses – and this is exactly where compliance with the guideline prevents corrosion from making the interface a problem.
Service call
You arrive for maintenance and measure the conductivity. Is it outside the specified limits? Then you immediately know what to do – and can convince the operator with clear facts.

Mixed bed resin Vadion pH-Control

Our Vadion pH-Control is a mixed bed resin that not only desalinates the water to < 100 μS/cm (equivalent to 0-2 °fh) but also ensures that the pH value of the filling water is within the required range.
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Conclusion – VDI 6044 as an opportunity for HVAC professionals

VDI 6044 is not a nuisance, but a tool. It gives you clear requirements so that you can operate cooling water systems in data centers safely, efficiently, and sustainably.
And that will become increasingly important in the future. Because the number of data centers is growing – and with it the need for HVAC professionals who understand not only heating water, but also cooling water.

👉 Our tip: Familiarize yourself with VDI 6044, use the experience from heating water treatment, and transfer it to the data center. This way, you will become a sought-after partner when it comes to the sensitive cooling of digital infrastructure.

Image: -PromptPlay- from Pixabay

Cooling water in the data center – why VDI 6044 is becoming required reading for HVAC professionals