Z-Wave / WiFi boiler switch WITH OpenTherm (found one, anyone using it?)

Hi All,

I just found a vendor selling an OpenTherm actuator for a boiler/central heater with a Z-wave AND WiFi capability. Here is the link.. It's €109,-- and I am willing to pay that, provided I know it will work with thermostats I already have and that report into my C7. Currently doing the full on/off switching, but with 5 rooms, 2 underfloor heating zones and the gas prices being what they are, it would be nice to optimize my boiler' gas usage by leveraging the OT options.

Does anyone know this vendor and/or product?

I have question outstanding to their tech department about what calls and functions are supported, but no feedback yet. They did tell me they run it successfully with a Fibaro HC2 but the marketing rep I spoke with was unsure about other platforms.

Interested in how you get on … may try one .. I have cascaded ATAG boilers , may not like that config.

Is your boiler actually OT enabled?

Its more than just the controller/thermostat you need - OT is a bi directional communication between a controller and the boiler.


I am using this IP based OpenTherm gateway http://otgw.tclcode.com/ and this requires a special driver that exist for several gateways (I maintain one of them), but not Hubitat.

For the actuator you referring to I would expect it to require a specific driver as well. Maybe you could access some functions with a generic thermostat driver, but they are one of the most complex drivers around with many variances. Only an actual test would tell I suppose.

Cheers Rene

if and when I decide to get one, I'll let everyone know how things go and how to set it up.

Yes it is. Most combination central heater / hotwater boilers sold in the Netherlands have this interface by default. Those that don't most often have an add-on board available for them. Our unit (Intergas Xtreme 35 CW5) has it installed as a standard and even has a RF interface to use RF based thermostats.

Hi Rene,

I am aware of that solution also and the problem of the driver. I wanted it pre-assembled but that was no longer an option when I looked at it. Since it is using an ethernet port, does it also have an accessible REST-API that covers all features of the OT protocol? If so, that would also work for me and I could just create virtual device based on a series of rules and conditions that would trigger the right API call. I would just need to find someone to solder it all together for me. Last time I did that (change pigtails on controlled LED strip) it worked, but it is not pretty.... LOL


Well, it is not that simple. The gateway spits out a nearly constant stream of status messages in a specific format and you can send commands to it. This is the Lua version of of a driver (should bebe simpler to do in Groovy) vera-OpenThermGateway/L_OpenThermGateway.lua at master · reneboer/vera-OpenThermGateway · GitHub.
This is one written in Java (Groovy is a subset of Java) openhab2-addons/OpenThermGatewayHandler.java at 2d957b7cdab75827c7995c380a16368428167003 · openhab/openhab2-addons · GitHub

So nice project to get you through December :slight_smile:

Cheers Rene

As bad as I am with soldering, I am worse at coding. So if I choose to do it like that, it will be a project that will finish no sooner then December 2025. :slight_smile: But thanks for the links... Maybe I can find someone to do it for me.

Anyone reading along looking for a nice project???

I have my dual ATAG Q38SR boilers but I am driving them from evoHome using on/off demand even though I have the evoHome Opentherm interface module. I know the boilers have individual OT interfaces but when cascaded ATAG say there are issue in utilisation of that OT bus by anything else.
Going to play and see, most of my needs are just reading status via OT, temps, % modulation on each boiler etc., and so the Q initially is whether that info is even sent so that it can be snooped.

Have a look at this site... They also supply custom boards to just do the monitoring. Might just meet your needs.

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