Vailant Heat Pump Controller displays "Communication Fault" when adapter is connected

[simonaldrich]

Hi

I have the following setup:

• Version 4 ebus/wifi adapter
• Vaillant Arotherm Plus Air Source Heat Pump
• Vaillant VZW AI Heat Pump Controller
• Vaillant SensoComfort RF Heating and Hot Water Controls

I've spliced my v4 adapter into the existing ebus connection between the Heat Pump Controller and the Heating Controls (please forgive the temporary loose Wagos etc): I understand that this should be acceptable for ebus connections since the installation manual states:

"You can branch the eBUS connection to the product at any part of the eBUS system" [^1] [^1]: VWZ AI Installation Instructions §3.3

When running ebusd I seem to be able to read to and write from the bus (I read and set the date and time on the Heating Controls as a test) however after a couple of minutes (at most) I get a "Communication fault" error code displayed on the Heat Pump Controller's display: The fault clears after a while but raises again shortly thereafter.

I think the problem must lie either in my connection or in the adapter since the fault is raised even when ebusd is stopped (i.e.:) the adapter is only powered on.

Hopeful someone can tell me what I'm doing wrong :pray:

Thanks very much, Simon :slightly_smiling_face: