[ebus] Some newbie question regarding ebus


first thanks to be patient, I am very new to OpenHAB and still in a heavy learning curve, I may have missed some obvious information.

In my journey to go to OH2, I want to connect my Vaillant boiler to check the status, like circuit pressure, change remotely the temperatures and then plan temperature change for holidays for example, to get a warmed house just before coming back home.

The boiler is already connected to a VRC470.

I still feel very confused about the ebus binding. Does the binding forward command to the controller, like the VRC470, or to the boiler ? How does both the controller and OH2 behave, so that the controller can still be used. I assume that it’s why the controller should be used in the binding, but it’s far to be crystal clear for me, if anybody could help me to have the big picture I would be very glad.

Where can I get the pressure, and other status, information. The VRC470 wiki page (https://github.com/openhab/openhab1-addons/blob/1.8/bundles/binding/org.openhab.binding.ebus/docs/json-files/vaillant-vrc470.md ) does not present these data. Should I make connection to both the boiler and the controller then ?

In addition, can the ‘diagnostic plug’ on the side of the VRC470 be used ? This plus is supposed to be connected to a vrnetDIALOG box. Do you know if this is a RS232 type serial line or is it just a connection to the ebus ports ? I’m aware of the eservice ethernet coupler, but I’m still evaluating the various possible options.

Hello @ChrisPe,

I’m not an expert for Vaillant devices, but you should maybe directly start with the new eBUS 2.0 binding. It is easier do manage because of the Paper UI Web Interface.

The binding works as an eBUS member on the bus, so you can communicate with every device. It depends on the heating system with way is the best. But in general I recommend that the heating unit should work on it’s on and you add only comfort features.

As developer of this binding I need help from other guys to add more commands to the binding. I can’t check this because I own a Wolf device. I hope I can add more and more commands until the first release candidate.

VRC port is RJ9 socket for connecting ebus enabled members. This is not RS232 port. Even if you buy vrdialog from Vaillant there is RS232 a converter between computer and heating controller.

Ok I see. Thanks for the clarification !

I fully agree on the way to let the system be manage as it supposed to by the VRC.

So the VRC470 is the device that hold the “intelligence” of the boiler and send commands depending of various data (external temperature, internal status, planification) and boiler is just acting as a slave ?

That would make sense to only interact with it through the binding, in limited way, to change the behavior, like changing the target temperature or getting data.

I can get the pressure from the VRC screen, so I guess it’s able to ask the boiler for it. I’ll need to go deeper then, but I’m not in a hurry, just in investigation phase :wink:

Regarding ebus binding v2.0, I cannot see it in the list of available bindings, neither on the openhab2-addons, is it not released yet ?

The binding is still in development, I will switch it from Alpha to Beta next release.

Oh awesome ! I think it’s time to order a ebus converter then :wink: