Vaillant VR33 Module for OpenTherm Support

[Rehan Saeed]

Vaillant boilers don't support OpenTherm but there seems to be a VR33 module you can install to enable the feature. Apparently its sold by Vaillant in the Netherlands where OpenTherm is more common. They won't sell it here because presumably they're just another evil corporation who wants you to buy their thermostats instead.

 

https://myboiler.com/opentherm/vaillant-opentherm/

 

I can't seem to find any documentation for how they're installed. I've seen people buying the modules from Dutch websites. Has anyone had experience with these modules?

[Radian]

No direct experience with that module, other than that I'm currently trying to understand the Vaillant/Glowworm ebus protocol which the VR33 module bridges to OpenTherm. I've built the electrical interface and got it talking over a connection to a RaspberryPi running ebusd. In principle, once this is working, an OpenTherm interface should be quite easy to knock-up.

[MJNewton]

Here's the installation manual, albeit not in English so you'll have to run the text through Google translate or similar!

 

Edit: There are a couple of photos here too which may be of use, although it doesn't look all that difficult.

Edited January 12, 2023 by MJNewton