Due to the oxygen diffusion through the capillary tube, a system separation of primary and secondary circuit is essential.
Even tubing and copper systems should be based on a separation system. Only by this separation it can be guaranteed that no corrosion particles of the main system can find its way into the cooling ceiling. For reasons of cost, a system separation for the tubing and copper systems is often omitted.
The separation is effected by a transfer station, which includes components like a stainless steel heat exchanger, circulating pump, expansion tank with cap valve, safety valves, isolation valves, thermometer and manometer. All the water-filled components that are used in the capillary tube system are corrosion resistant on the secondary side. This implies that the water quality remains in a good quality for a very long time.

Main distribution board in an office building in Berlin

Separating station for the Maschari Center Berlin
For the separation systems, there are two different versions:

Central transfer station in the EU Embassy in Georgia

Ring line for cold supply in the office building Mosse Palais Potsdamer Platz Berlin

Separating station with central distribution in Munich