Vaillant Smart control - are my assumptions correct?

[thebaldfox]

Just took over a new property that has an EcoTEC pure 637 installed, separate HW cylinder, honeywell Evo home programmer (t6).
I'm upgrading and have bought the following items after doing a bit of research and would like to get some confirmation of my assumptions:

Purchased:
VR71 - I have a single heating circuit and HW, but would like the ability to add a 2nd in the future (UFH).
VRC720F - wireless Sensohome controller - I want to use weather compensation & load compensation for efficiency.
VR921 SensoNET - gateway to allow us to control the heating whilst we're away from the home or via phone/tablet.

Assumptions:
1) All the above, plus the boiler are able to be daisy chained for eBUS (i can insert two sets of wires in the same connection allowing eBUS to be linked onwards (see diagram).

2) Using a VR10 sensor that comes with the VR71 this can be used in the pocket of the HW cylinder to monitor/control temps of HW.

3) The wireless temp sensor that comes with the SensoComfort rf will allow me to use weather compensation.

Questions:
1) Will the above actually allow me to lower the HW cylinder temps, but retain a boost to kill off legionella every X days/weeks etc?

2) Is there anything else I am missing?

3) In the future, should we go for individual TRVs would there be any other modules I might need to purchase?

4) The VR11 that comes with the VR71 isn't needed in my set up.

5) If I wanted to add a secondary circulation pump, would this be easy to connect to the above?

Thx

 

[emerylloyd]

IMO (sorry for cr*p formatting)

Assumptions:
1) All the above, plus the boiler are able to be daisy chained for eBUS (i can insert two sets of wires in the same connection allowing eBUS to be linked onwards (see diagram).

Correct.

2) Using a VR10 sensor that comes with the VR71 this can be used in the pocket of the HW cylinder to monitor/control temps of HW.

Correct.

3) The wireless temp sensor that comes with the SensoComfort rf will allow me to use weather compensation.

If an outdoor sensor yes.

Questions:
1) Will the above actually allow me to lower the HW cylinder temps, but retain a boost to kill off legionella every X days/weeks etc?

Yes, separate HW temp set as "main" temperature then boost function programmed. Allow for heat loss in regards to stored temp and any secondary return you add.

2) Is there anything else I am missing?

I don't believe so.

3) In the future, should we go for individual TRVs would there be any other modules I might need to purchase?

Mechanical TRVs? No. Digital TRVs I'm unaware if Vaillant do them and haven't wired 3rd party into VR71 before.

4) The VR11 that comes with the VR71 isn't needed in my set up.

Strapped to primary flow pipe before any zone valves, at least this used to always be the case. Used for weather comp and hot water flow temps on primary side.

5) If I wanted to add a secondary circulation pump, would this be easy to connect to the above?

Yes.

 

[thebaldfox]

Thats brilliant @emerylloyd Just what I was hoping for.
I did have a couple of follow ups if ok.

4) The VR11 that comes with the VR71 isn't needed in my set up.

Strapped to primary flow pipe before any zone valves, at least this used to always be the case. Used for weather comp and hot water flow temps on primary side.

5) If I wanted to add a secondary circulation pump, would this be easy to connect to the above?

Yes.

I was under the impression that the wireless external sensor would take care of the weather comp, how would using a VR11 internally benefit the set up? I'm a few steps behind but trying to catch up!

The circulation pump I've got at the moment isn't working. At some point I'll want to replace it, but not sure where abouts exactly you'd insert that into the circuit?

My heating engineer will install all of this, but I just want to make sure I'm able to provide him the correct parts and instructions for set up!

 

[Deleted member 281264]

I've got sensocomfort vrc720f, a vr92f for a second zone and vr71 ... I didn't bother with vr920/21 as the app looks dogshit.

If you are adding UFH to your setup you will need hydraulic seperation at the boiler (closed couple tees or low loss header) and also an electronic mixing valve if you want fully weather compensated underfloor heating along with the ability to run 3 different flow temperatures

In my setup there is no need for a VR11 sensor, just 4 x vr10's

One for system flow temperature

One for cylinder pocket

One for UFH flow

One for Radiator circuit flow

All pumps can be wired into the vr71 and controlled by that

If adding UFH you will need two pumps outside of the boiler, one for UFH, another seperate one for radiators.

 

[thebaldfox]

I've got sensocomfort vrc720f, a vr92f for a second zone and vr71 ... I didn't bother with vr920/21 as the app looks dogshit.

If you are adding UFH to your setup you will need hydraulic seperation at the boiler (closed couple tees or low loss header) and also an electronic mixing valve if you want fully weather compensated underfloor heating along with the ability to run 3 different flow temperatures

In my setup there is no need for a VR11 sensor, just 4 x vr10's

One for system flow temperature

One for cylinder pocket

One for UFH flow

One for Radiator circuit flow

All pumps can be wired into the vr71 and controlled by that

If adding UFH you will need two pumps outside of the boiler, one for UFH, another seperate one for radiators.

Got it. Thanks for that. The UFH is indeed for another time (year!), just want to get a handle on the current set up and get things running better.
If we can get the single heating zone and HW set up correctly, I'll be chuffed.

I've never had a secondary pump before, but it appears to have failed, so am debating whether to leave it out of the mix altogether or get it replaced at the same time. Good to know the VR71 can control that aswell. Is that likely to be on/off control only (presumably wired to an output) or is there some smart capability that can be applied to that too?

 

[Deleted member 281264]

The pumps are connected to the relay switch on the vr71 so yes they are on and off, but you can get modulating pumps with settings like proportial pressure and they work very well. UFH pumps want constant pressure.

You want to make sure your plumber sets up your system for hot water priority, so that when the cylinder calls for heat the heating will shut off and boiler will go full pelt to charge the cylinder ASAP.

I think you could run your rads and secondary circulation pump off of the same external pump.

How big is your house? the 637 is likely hugely oversized unless you have a 10 bedroom mansion

 

[thebaldfox]

How big is your house? the 637 is likely hugely oversized unless you have a 10 bedroom mansion

It's a 4 bedroom detached, with about 7 rads on it. The whole house has been renovated almost with commercial/industrial level bits and pieces. I have a diesel back up generator the size of a Nissan micra, 3 phase etc. I just want everything set up efficiently and if necessary tuned downwards, to try and ease the bills. I get the sense the previous owners didn't care about energy!

Are there any other tips you would suggest I need to make sure the plumber sorts? I'm assuming actually turning on Weather and Load compensation in the control panel is relatively straight forward?

Also If I do add in a new circulation pump, would you run it 24/7 or only say when the boiler is on? Sorry for such a basic question, I'm trying to get up to speed quickly!

 

[Deleted member 281264]

637 is oversized for a 4 bed detached, mines larger and the 630 is oversized for that so yours will cycle a bit

I'm not sure regarding your question about the circulation pump. It depends how your setup is piped up.