Added VMS8/D "vmd01", SW0108, HW1703 (AuroStep Plus Drainback solar controller)

[pagaille]

Based on the file pms.csv which looked the most close to the VMS I use (internally labelled "vmd")

Only the temperature sensors, solar pump 1 flow rate and PowerOnCounter are currently supported. There are a lot more to find but that's difficult without any documentation and without any other Vaillant device talking on the bus : my boiler is installed autonomously.

If someone having a good knowledge of Vaillant ebus messages wants to help I can provide various sets of registers values taken a different working phases.

I certainly would like to be able to find the settemp (water temperature target).

[cingolo]

Hi Not sure if i can help here. My VMS8 boiler is connected to an ECoTec via C1/C2 connection so no ebus connection. EcoTec is then connect via ebus to the VR 921 module.

[pagaille]

How strange ! In my understanding the c1/c2 contacts are used for non vaillant heaters. But I may be wrong.

[cingolo]

To be honest not sure why they have connected in such way the boiler to the heater. Indeed from the Multimatic app i cannot control the boiler or check the water temperature. This is the reason why i was exploring other avenues by installing the ebusd in a Raspberry.

[pagaille]

You might also simply connect them together. It’s plug and play asfaik. Keep us updated.

[cingolo]

You meant connect the boiler temperature sensor to the heater and disconnect the C1/C2 otherwise i don't see other way to connect them. In this way i should at least get the water temperature on the thermostat but i would not get anyway the solar sensors values so maybe it is better just integrate the boiler with Home assistant via eBus and then fetch the other heating data via Vaillant Cloud API. At least i had this in mind and i found your ebusd VMS8 configuration.

[pagaille]

I meant connecting the ebus to the rest of your installation (which is much more than a simple temperature sensor) and disconnecting the c1/c2. That way the vr921 gateway has access to all the parameters shared by the VMS. It's unclear how it would take advantage of it but we might learn a lot by spying on the ebus using ebusd. I'm especially interested to find out the address of the solar yield since my CSV is far from complete to say the least.

[cingolo]

I can run some tests, no issue but it might take time. Just installed the ebusd and I need to go through the documentation how decode the messages and make the ebusd working with the isolated VMS8 boiler.

Current implementation: Vr921 --ebus-> Heater EcoTec C1/C2 --- BoilerVMS8 Test implementation: Vr921 ---> ebus ---Heater EcoTec---ebus-- >BoilerVMS8 ---> ebusd Raspberry  ( keeping the C1/C2 connection or T7 shouldn't make big difference though).

[pagaille]

Thanks for trying !

keeping the C1/C2 connection or T7 shouldn't make big difference though

Might be. The c1/c2 instruct a heater to heat and run the circulator to warm the boiler, which could interfere with the informations exchanged on the ebus. I would try to remove it but you might get a cold shower of course 😊