Vaillant VR33 (with Nest) and VR66

[asoffe]

Does anyone have experience of using a VR33 (for Heating OpenTherm control with Nest) and a VR66 for Hot Water Priority with Vaillant system boilers? I'm specifically using an EcoTec plus 624
I've got a system working with a Nest and VR66 to provide hot water priority and it works well with separate cylinder charge and heating flow temperatures. Currently this is all connected to the Nest using the switched CH and HW controls. I'd like to use the OpenTherm capability of the Nest for the heating but have questions about how the VR33 and VR66 coexist if they can at all. There is no timer or thermostat connected to the VR66. The only control input to the VR66 is the cylinder stat & nest HW switched line.
I'm hoping that the VR33 just behaves like an ebus thermostat and would work alongside the existing setup (with removing the switched CH controls on the boiler) but would love to know if anyone has experience of going into this level of detail.

 

[Daw____]

I was able to get the Opentherm, Nest and DHW priority to work once I also installed the VR66, which effectively eliminated the S plan system. The wiring in logic is exactly as you say above Plum47.
I have written about all the steps here in a clean thread (I can't link, you have to search for it)

Vaillant Ecotec system boiler with VR66 and Opentherm (Nest)​

Hi, Do I need any of this if I am using Valliant ecotec pro combi boiler with VR33 OpenTherm and Nest ?

 

[Plum47]

Hi, sorry to jump in. Do you mean the 24V RT connection bridge?
I am also thinking to connect Vr33 openTherm module to my Vailliant ecotec pro24 to work with Nest gen3.

Hi Daw

I think what @asoffe said is that if you remove the on/off type 230v control, and switch to a low voltage digital (eBus) connection, you should have a bridge on the "24v = RT" block on the PCB, which is a white block. Then you will connect your + and - on the eBus block if you want to use eBus, which is a orange / reddish block.

Hi, Do I need any of this if I am using Valliant ecotec pro combi boiler with VR33 OpenTherm and Nest ?

Tell us a bit more about what you currently have and what you are trying to do so we can try to help.

 

[JamesBaby]

I'm setting up the VR66 and have installed the VR33.

Please can someone confirm how to wire 2 Nest stats for the 2 zone system I have. Do I put the VR33 OT wires to both NEST boxes?

Is two zone control possible with this setup. It's currently S plan with Unvented cylinder.

What version of VR66 did you use, there's VR66\2 which is most recent which they say has updated software.

 

[ShaunCorbs]

I'm setting up the VR66 and have installed the VR33.

Please can someone confirm how to wire 2 Nest stats for the 2 zone system I have. Do I put the VR33 OT wires to both NEST boxes?

Is two zone control possible with this setup. It's currently S plan with Unvented cylinder.

What version of VR66 did you use, there's VR66\2 which is most recent which they say has updated software.

You can’t wire two nests in opentherm only one stat in the system

 

[NordoD]

Really interesting thread - thanks for sharing experience/knowledge. My house was renovated ~10 years ago.
System comprises Vaillant 624 EcoPlus system boiler with 3 CH zones (rads up, rads down + UFH (HeatMiser UF3) ) plus HW in an unvented Main 210L tank); The UFH has 4 zones with 4 wall stats (as an aside, I think this is unnecessary now as the areas are mostly open plan so a single stat would suffice).
"Interestingly" the two rad zones share a common stat - I think this is fundamentally flawed but rather than fix it I'm looking to do a wholesale upgrade to get more efficient by using modulation + decent controls.

I've ordered a VR33 (FYI you need to create an account to get UK shipping - a guest can only do collect)
As per the excellent info, I was going to get the VR66* but am I right in thinking this will do HW plus one CH zone only?
If so the confusingly named VR61 seems to be twin CH zones + HW capable - could be used instead. is that correct? (I'll probably merge the rads up /down but TBD . I guess my final question is similar to James in that how would this (OT) work with two stats?

Thanks

 

[JamesBaby]

You can’t wire two nests in opentherm only one stat in the system

Ah shucks. It means Ill have to do a standard S Plan, system boiler 2 Zone NEST setup.

So now I have a VR66, VR33 and VR10 NTC to off load as it’s no use to me.

Unless, does anyone know of any Opentherm programmer/thermostats that will deal the CH plus HW, and a 2nd upstairs CH zone?

Or equivalent Vaillant controls now that I have eBus routed to near the valves?

 

[ShaunCorbs]

You could do weather comp and run the nests as stnd on off controls

 

[JamesBaby]

You could do weather comp and run the nests as stnd on off controls

Ok, I’ll look into that as well. Thank you.

 

[Bruffy84]

So now I have a VR66, VR33 and VR10 NTC to off load as it’s no use to me.

Did you still want to sell these? I need to buy some. Thanks

Great helpful thread

 

[JamesBaby]

So now I have a VR66, VR33 and VR10 NTC to off load as it’s no use to me.

Did you still want to sell these? I need to buy some. Thanks

Great helpful thread

I Have the VR33 available. I have DM's you.

 

[Vee]

Honeywell Evohome have an Opentherm bridge which can talk to the VR33.