Connection Error in combination with VRC 410/420

[DrSpaltenstein]

I made some modifications of the code to use in my environment. (Ecovit VKK226 (2004) + VRC420 + ExtensionPCB for 2nd heating circuit)
First I tested it on the workbench with a spare main PCB of the VKK controll (only PCB of the heater + VRC420 unit)
In this setup it basically worked, of course sensor values were missing as no sensors were connected, but some basic communication was possible. I also added some additional Sensors (2. Pump, Water boiler temp...).
Then I connected the ESP to my heater in the cellar and here it only works for some minutes, then the VRC display shows "Communication" error and it stops working.
As mentioned in the other issue post there might be some conflict on the x6 bus.
Has anybody an idea how to solve this? I only want to see some values in homeassistant, dont need to change anything. So any ideas how to modify the ESP in a way that it doesnt influence the bus?
Maybe increase the update intervall?