How to choose the stainless steel manifolds for radiant heating system

Pre-assembled manifolds are used to distribute heat-transfer fluid inside a system.
They can be used in traditional radiator systems, and innovative under-floor radiant systems.

Stainless steel manifolds are particularly suitable for heating systems: they avoid any unnecessary waste and ensures an elevated level of thermal comfort.


Over the decades, stainless steel gained increasingly more importance and spread into new industrial sectors. Today it has become the basic component for the construction of radiant heating parts and accessories, demonstrating the evolution of high comfort heating systems. With this alloy, the main problems relating to the traditional distribution manifolds, made of brass alloy or composite material, have been overcome.

Introducing the use of stainless steel in the production of manifolds, able to offer the client considerable cost savings, together with several technical advantages, which cannot be achieved by using manifolds made of brass and composite material. In this field, austenitic steels have found widespread application (AISI 3xx series), featuring percentages of Chromium (18÷20) and Nickel (8 ÷ 12).

  • Resistance to corrosion;
  • Resistance to fire and high temperatures;
  • Lightness;
  • Compliance with hygienic requirements;
  • Wide range of design applications;
  • Ease of manufacture;




In developed markets, such as those in Northern Europe, the use of this material in the field of thermo-hydraulic systems has been a well established practice for many years. Just think of the use of pipes and fittings for domestic water supply systems, in addition to condensing boilers. These, due to the formation of condensate for the recovery of the latent heat of the exhaust fumes, require many internal stainless steel components, since the internal environment of these heat generators is very aggressive.

Condensing boilers are the highest form of technology applied to radiant systems: thanks to their structural and functional characteristics, they can be combined perfectly with these heating systems (with return temperatures around 25°C).

The use of stainles steel manifolds thus enables a continuity of the metals used to produce a radiant system: metals or similar alloys, in presence of an electrolyte (in this case, the water system), can be placed close to each other, without generating electrolytic corrosion. A phenomenon that is triggered by the proximity of different metals: this type of corrosion is activated like a torch (i.e. “galvanic cell”).




The evaluation of costs, related to the useful life of a system, are today a major issue for technicians and design engineers. The “Life Cycle Cost” concept can be enhanced by the use of stainless steel, since its use eliminates the corrosion phenomenon (either electrolytic or due to stress within the alloy).

In the light of the properties described, it is easy to imagine how the number of design engineers and companies involved in installing stainless steel manifolds will tend to grow increasingly. In fact stainless steel combines all the objectives that a modern system must comply with:

  • protecting the environment;
  • reducing the manufacturing and management costs;
  • high thermal comfort.



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How to choose the stainless steel manifolds for radiant heating system
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