Vaillant VR33 OpenTherm Module with AroTherm Plus ASHP???

24 Jan 2024
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Hi All,

I am curious to hear if anyone knows if the Vaillant VR33 Module that can be used to convert Vaillant Boilers to support OpenTherm also works together with the Vaillant AroTherm ASHP range?

As far as I can understand Vaillant uses a very old protocol (eBus) for communications between Vaillant controls and the OpenTherm protocol is a much newer standard that is also used widely in the netherlands.

I am very interested in seeing if I can get the Homely device to work with an AroTherm Plus system.

If anyone has any experince installing a VR33 with a Vaillant Arotherm ASHP I would love to hear from you!
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Do any heat pumps use OpenTherm? Something I pondered a while back. And there's a second linked article below asking the same thing at posts 8/14 and 12/14.

Do the heat pumps you are considering work with OpenTherm? In fact, do any heat pumps? I've just been reading this discussion. It's a bit above my head, but it seems to include a discussion as to whether OpenTherm, or indeed any type of load/room compensation, works with heat pumps.

@MNW67 Thanks for the response!

I actually found a really interesting article on the home automation site, which uses the myVaillant API. I would imagine that if this is possible then Homely potentially could do the same!

Does anyone here know the difference between the Vaillant sensonet VR921 and the VR940F??? There is almost £100 price difference but I can’t see what the difference is other than the sensoNet VR940F also supports Apple HOME KIT???

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