Where heating water should be treated—and how to integrate the technology correctly

For those who don’t just fill tanks, but take responsibility

Heating water treatment is more than just an “add-on” – it is part of the system design. But to ensure that the water quality is really right, it is not enough to simply screw a mixed-bed filter in somewhere. The decisive factor is where and how the technology is integrated. Because only those who understand the system properly can get the most out of it – both technically and economically.

Whether it’s a new installation, renovation, or system maintenance: the quality of the heating water determines how long the technology will run without problems – and whether you’ll be covered in the event of a complaint.

Initial filling: The ideal moment for clean water

The initial filling is the perfect time to set the right course. Using fully desalinated water from the outset provides the system with the best conditions right from the start – without the need for additional corrections.

In order to comply with the values recommended in VDI 2035 (hardness of 0.3 °dH, Conductivity ≤ 100 µS/cm and pH value between 8.2 and 10.0 or 8.2 and 9.0 for aluminum components), the water is treated, e.g., with the help of our Heaty Ferriline No. 2, and thanks to Vadion pH Control, all hardness components and aggressive anions such as chloride or sulfate are removed.

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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But don’t forget: If it cannot be ensured that the system is free of chips, sand, or other coarse contaminants, it should be flushed in accordance with DIN EN 14336 before commissioning, e.g., with normal drinking water.

Treatment in circulation: Cleaning instead of chemical post-treatment

Filtration in circulation mode is particularly useful for existing systems with dark heating water, sludge, or magnetic particles.

Unlike chemical desludging agents, this method offers a mechanically clean solution without introducing additional substances into the system. Combined with magnetite separation, you can effectively remove iron oxides without having to interrupt operation.

Heaty Ferriline No. 2 is also ideal for this application, as it is a complete device that is suitable for continuous bypass operation (more on this in a moment) and, in addition to our mixed bed resin, also features magnetite and sludge filtration down to 1 µm .

Bypass treatment: Flexible during operation

Not every system needs to be drained to improve the heating water. With bypass treatment, existing systems can also be desalinated retrospectively – while normal heating operation continues.

This method is particularly suitable when the pH value or conductivity deviates from the norm, but the system cannot be shut down. A bypass circuit in the return line permanently feeds a partial flow of the heating water through a mixed bed. This allows you to correct the water gradually without leaving the customer in the cold.

Did we mention that you can also use Heaty Ferriline No. 2 in bypass mode? 😉

Replenishment: Often underestimated – but often the trigger

Even the best initial filling is of little use if unsuitable water enters the system again during replenishment. And that happens more often than you might think – often directly via the domestic water connection, without any protection or treatment.

The solution is simple but effective: A permanently installed make-up water unit with a system separator and mixed-bed resin, such as our Heaty Complete Advanced and PROfessional.

Heaty Complete Professional

The Heaty Complete PROfessional is the world’s first smart IoT top-up system incl. Cloud connection – fully automatic, leakage protection and digital water meter.
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The condition of the resin itself also deserves attention: it must be replaced after two years of service or when it reaches its capacity limit.

As soon as intervention is necessary, this can be detected in the Heaty Complete HOME by the discoloration of the resin and in the Heaty Complete Advanced and PROfessional by a visual and optical signal. The latter even proactively informs you via the cloud portal that a replacement is due. The UWS cloud portal also allows you to view the operating status of each PROfessional replenishment.

The larger devices in the Heaty Complete GLT series can be conveniently integrated into the building management system.

Heaty Complete GLT

Make-up unit with BA system separator for larger heating and cooling systems incl. Connection to the building management system.
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The right solution for every system

Whether it’s an apartment with heating circuit distributors, a multi-family house with a central system, or a heating network with a transfer station—the requirements vary, but the principles remain the same: clean water, stable values, and reliable make-up water.

With the modular solutions from UWS, you can respond flexibly to any system size – mobile or stationary, temporary or permanently installed.

Conclusion: Well integrated means permanently protected

Heating water treatment is not a question of cartridge size, but of correct implementation.
Those who know where what should work and how prevent corrosion, increase efficiency, and protect their work in the long term.

Our recommendation for HVAC professionals:

Plan the integration with just as much care as the system itself – and use the appropriate UWS solutions to comply with standards, prevent damage, and ensure long-term safety.

Image by Peter H via Pixabay