Heating circuit distributor flushing, circuits do not close completely

Amazing what is supposed to be lobbying nowadays...

that it wouldn’t be dramatic if a circuit were flushed with normal water, since the amount of water compared to the total volume is relatively small.

Apparently the colleague either has no idea or works according to the usual motto "we have always done it this way"

By flushing with tap water, you are introducing not only calcium and magnesium salts into your system but also oxygen, which has no place there. Because even underfloor heating systems have fittings and pipes made of red brass, steel, and brass, and all of these like to react with tap water...

ok, thanks for the answers so far, even though they are not very positive and I don't know what to do now.

But back to the original question, which has remained unanswered so far:

If I close all my HK branches via the valves in the HKV. How can it be that there is still a flow? When I flushed, I introduced water via the maintenance supply, all valves were closed and still water flowed out of the maintenance return. Ergo: There was a flow despite closed circuits.

Are the valves so weak that they can be pushed open by the water supply or could it be that dirt is stuck in there, preventing proper closure?

If everything is installed and sealed correctly, there should be no flow through the circuits. However, I have had the case that the gasket on the valve was defective and the circuit no longer closed. It kept getting warm even though it was off....

Thanks for the clear statement. :)

btw: Are there water tests available for purchase that can determine/test the pH value and all other information relevant to heating water? Maybe it’s better if I refill the system with osmosis water before something gets permanently damaged?

hello, yes there is. easiest in the pet store as you also use osmosis systems for aquarium water.