Gira 1220 - thermal valves - knocking sound

[Houseofdreams]

Hi,

I don't know if this is the correct place to be asking this question, because it has to do more with the KNX hardware then programming I think.

I have a Gira 1018 coupled with 5 Gira 1220's. They are each connected to a radiator trough a "collector" (a copper pipe with connections where all the tubes from the radiators connect to, I don't really know the correct translation)

The 1018 is programmed (1byte continuous mode) and all hardware should be working normal. When the valves open or close (the do really slow) a sort of knocking sound appears at the collector. Does anyone here had this kind of problem, or does this sound familiar?

What could be the problem here? It' s all first grade hardware so no cheap stuff...

[koenen]

Me2

I also noticed someone knocking at my heat pipes and suspect the valves. I think it's a mechanical problem with the valves, not the KNX thermal drive.

[Houseofdreams]

Yeah it probably has to do with the valves in the collector itself, my goal was to find people who had this same problem, to find out what they did to fix it.

There are some bypass valves to attach to the collector, but this is a KNX forum, not a heating installers forum

The sad thing is that this heating with KNX is still not widely spread, so dedicated fora about this kind of problems are hard to find, if they exist all together...