Vaillant Thermostat / Ambisense pack - all the gear no idea

25 Nov 2006
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United Kingdom
Hi, would appreciate some advice re installing a Vaillant Sensocomfort wireless thermostat VRC720F. It comes with control unit, base station and outdoor temperature monitor.

I've also bought an Ambisense starter pack which has three TRVs and a VR920 internet gateway.

I'm competent but no expert so my question is whether they're straightforward enough that I could install them myself or whether the controls require lots of data set up and authorisation codes that are only available to Vaillant approved installers.

I've got an Ecotec plus boiler, but not one where you can plug in the thermostat so I'd have to connect it manually. Thanks.
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I'm answering my own question here so that it might help someone else in the future.

It was straightforward to install the VRC720F wireless thermostat and VR920 internet gateway - wire both into the BUS terminals on the PCB (X16). Polarity doesn't matter. I used 0.75mm2 2core multi-strand. Retain the bridge between 3 and 4. (If you're using the boiler's own clock I think you may need to disconnect it.)

If you get 'installation not compatible' on the VRC700 or Sensocomfort app (both work with my set up) it's likely a software problem. Go to General Settings on the app, delete the location, then delete the app and start again. (Vaillant support were helpful.)

The app takes a bit of getting used to but being able to boost/override the timer programme by room is useful.

I had a straightforward 'one zone' set up i.e. combi boiler heating whole house. If you set the bedroom radiator to come on before you wake up you'll probably get woken by the whirring of the TRV adjusting its settings but worth the trade off of being able to heat the bedroom at different times to the living room. I'll probably get another Ambisense TRV for the bathroom so I can also set that to a different timer programme altogether.

you seem to have exactly the same setup that I was looking at in order to upgrade my system, I hope you do not mind if I ask you a couple of questions.

Do the VR50s simply operate the radiator valve ON/OFF depending on the temperature set vs. the ambient temperature or do they also send a request to the boiler (via the thermostat, I suppose) to provide hot water ?

If it is so, which device has precedence, the VR50 or the thermostat itself ?

Just an example to clarify the question.
Consider a simple setup with the 720f in the sitting room and a VR50in the bedroom radiator.
During the night the 720f is set to, say, 18 degrees and in the room there are 20 degrees.
At the same time the VR50 in the bedroom detects a temperature in that room (e.g. 18 deg) that is below the set temperature (e.g. 19 deg).
What happens ? The VR50 simply opens the radiator valve but the radiator does not warm up because the thermostat is preventing this, or does the VR50 actually send a "heat" request to the boiler that is honoured and the radiator in the bedroom starts warming up (but also all the other radiators that do not have a VR50 installed) ?

Are you happy with your system ? Does it work as you expected ?

Which app are you using ? Does it work well ?

Thanks a lot in advance !
I appreciate this is an old thread and the OPs may long have sorted their issues but I'm doing a response as this thread is google-able (which is how I found it).

I have 13 VR50s. (And two VR52 repeaters) And a VRC720f.

Largely in a set-up like mine, the VRC720f (SENSOComfort) is redundant. Since each room has one or more VR50s. (I've chosen to create each VR50 as a zone. you can group VR50s into a room zone if you like).

The VR50 do indeed individually 'call for heat' - essentially the boiler (or other heat source) sees the 'desired temperature' as the highest temperature of any of the VR50 TRVs - it will set this on the VRC720f display as well.

I've not tried changing the desired temp on the SENSOComfort because there are no zones that aren't smart-TRV'ed in my setup but I imagine it will set the desired temp for any 'non-smart' emitters you have, the boiler (or other heat source) will fire if necessary, and the VR50 controlled rads will not heat up further if they are below the SENSOComfort setting you are using for the rest of the property.

They're good. The app is 'OK'. many complained about the old SENSOapp but there are things I prefer than the newer 'MyVaillant app. Now the MyValliant app finally supports VR50s, the SENSOapp is no more.

Hope this helps someone!
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Sorry to GiAi for not seeing you post back in December 2022, I hope you got the answers you needed.

After installation (March 2022) I found the SensoComfort app was very unstable and not particularly user-friendly. Vaillant said a new app was being developed but it's taken 2 years. The new MyVaillant app was released in March 2024 and is more user-friendly but I still had issues which they said would be corrected by software update. It seems to have sorted some but I'm still unclear on others.

GJones2021 - maybe you could help me? I have 2 x TRVs in Room and 1 in Room 2. In the App, on Overview. the first option is Control, within which the options say Heating, cooling and domestic hot water. But when I select Control, the only option I get is Domestic Hot Water. Are you seeing Heating and Cooling too? (Not sure what Cooling is!). If so, what kind of control does it offer?

I don't know if it relates to more complex set ups but as I'm not currently there I don't want to play around just in case I end up with the heating on 24/7!

Hi SJRSJR - yup, I see exactly the same thing in the MyVaillant app.

I think the layout in the MyVaillant app is very confusing - unlike SensoAPP, there isn't really a Home Screen, so to see any general setting you need to select a zone/room/TRV (in my case because I defined each TRV as a room they are synonymous) and then you get access to general settings such as 'control', network settings' - that seems most odd!

My guess regarding 'control' is that if you had A/C, (or other Vaillant 'exotics' not typically seen in the UK like Forced Air Heat Recovery units it may have more relevance?)

I think you might see 'Heating' and be able to control heating in a situation where there were no TRVs but standard wall stats? I thin the usual UK domestic setup probably has a roomstat upstairs and one downstairs - and only then if there are two zones?

I've also not played with DHW - since I have a combi. I suspect if you have a typical S- or Y- (or X-) plan system then you can override the programmer for the cylinder with a hot waster boost?

I manage my heating by having a timer programme for each TRV (and again, annoyingly, unlike the SENSOapp, you can't copy one TRV timer programme to another - or not that I've found.)

FWIW, my experience with the VR52 extenders is they are pretty rubbish. The app often shows a number of my TRVs as unreachable (although they still work - so maybe the UI is misleading in that they accept a broadcast like a change of setting but may not show up in a periodic poll hence the unreachable status
Thanks GJones21, that's really helpful.

Yes, it would be handy if you could copy the timer settings to another 'room' not just another day. Maybe make the suggestion to Vaillant via the app's 'send feedback'. They've previously responded quite quickly

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