Discoloration of heating water (only the supply line)

Hi everyone, I have noticed that the supply line on our underfloor heating at the heating circuit distributor is discolored.



You read all sorts of things about this, from harmless biofilm to rust or sludge buildup?

What seems strange to me is that only the supply line is discolored, and not the corresponding return line? The heating water should have been mixed during the warming up of the screed, right?

Has anyone here possibly experienced this or knows what it is?

Looks kind of strange, the [Taccos] still seem to be clear. Since when has the underfloor heating been running?

There is nothing strange about it. Just built according to the motto: "That's how we always do it."

Let me guess, you have a MAG made of simple steel and the heating water was not demineralized at all or only inadequately. Well, and possibly some other minor things.

But why are the Taccos and the return then clear?

Because the water is not yet saturated. After a heating period, everything will turn brown. There's just not enough dirt in it yet, but through the ongoing chemical processes and heat as a catalyst, it will definitely happen. It's not like this is something new.

The system has been running since the beginning of January