Vaillant integration for new Tado'er
Good day, I'd like to request some clarification on specifying components for a new installation. As I am confused having only ever had one heating loop (combi boiler, apartment living, only controlled by boiler time clock and thermostatic radiator valves).
Situation is: Normal 1930s house (UK), 3 levels, 150 m2 total floor area. New refurb, with a first time boiler installation (total re-plumb). The boiler is a Vaillant Ecotec plus 635 system boiler. There are 4 heating loops each with it's own zone valve. The zones are:
- Hot water tank (250L unvented)
- Wet underfloor heating zone
- Radiator zone A (ground floor, separate to UFH)
- Radiator zone B (bedrooms & 2 bathrooms)
I have put a diagram of the boiler plumbing in the attachments. There are currently no heating controls, apart from a Salus wiring centre that the installer has provided. I m happy to bin this if necessary.
What I want to achieve:
- Automated control to several time periods for each zone - 3 minimum
- Temperature modulation on the heating flows
- Wireless zone controller for the UFH zone
- Wired zone controllers for the radiator zones*
- Temperature limit on the UFH so it doesn't get too hot when the radiators aren't running - modulation should do this, or a floor thermostat in the UFH package.
- Primarily manual control through a local programmer, not control through an app. App is a useful toy but we don't want it being the primary controller.
- Separate control of some of the radiators, to allow different temperatures within their zones. e.g. the attic bedroom to run more heating without the lower bedrooms becoming too hot at night, or heat just the office during the day time for home working.
I would like to use Tado-X mainly because the thermostats look a lot nicer than V3, but I am aware that eBus and Tado-X aren't natural partners.
Tado support have advised 2 options
- V3+ wireless starter kit for combi boilers + extra wired stat's, but I can't have the smart TRVs
- Just smart TRVs with a bridge-X but then I can't directly control the boiler and hot water
I am confused. Why do I need a system for a combi boiler to control a system boiler?
If I go for the TRVs and Bridge-X, how do I control the hot water?
Is there a better (simple) way?
Thank you
Answers
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Doesn’t sound like Tado would be a good fit. I’d expect a a holistic approach from the design and build of the heating system.
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Thank you for your reply, I agree that would be sensible but sadly I've not been involved with any of that and now I have to pick over the options at the end. The builder has specified and installed the system and is now asking us to provide the controls. We have been asking them since the beginning for some support in this because of course without knowing what they intend to supply, we have no idea what to spec ourselves. Had we known from the off that this was now an extremely complicated area - I'm a chemical engineer and I'm stumped on the control side of it - we would have specified the boiler and tank and offered to provide it rather than them. We are where we are.
If you can offer any more insight that would be great. Tado support seem to think there are options, albeit with compromises like having to run the hot water from the boiler's internal programmer. But Tado support respond to one email per day on average.
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Hopefully there was method to the madness of the builder installing it. Let’s imagine he’s calculated the heat loss and sized the emitters accordingly.
I’d aim to get it set up with weather compensation and run with minimal set back overnight. Run the hot water with PDHW, aka hot water priority. Use Vaiilant controls and wiring centre.
I’d suggest engaging someone that knows what they are doing. You might get suggestions involving low loss heaters and pump groups, but I’d hope you could avoid that.
Once you have an idea of what kind of heat you need for design temp (maybe -2 unless you live somewhere chilly) and perhaps some mass flow calculations, it’ll become apparent if it’s viable.
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Thank you. The Vaillant controls and wiring centre are close to £1000. More to the point their thermostats are enormous and very ugly, and will obviously be in prominent positions. So the problem we have is finding a third party solution that gets the best out of the boiler, which isn't akin to buying a Ferrari and putting a 1.0L Ecoboost engine in it.
One leading question I have - what is the wireless receiver? In my mind it is a wiring centre that can also make a wireless connection. So you use it to replace the existing wiring centre and connect one Tado wireless device. IS this right?
Tado V3+ can do eBUS if we go for the EU version which is sold in UK as the wireless kit for combi boilers. That is the advice from Tado Support, along with add-on wired thermostats to control the heating zones. These need to be wired to the zone valves directly. And there's my confusion because I am not clear, if the smart thermostats connect DIRECTLY to the zone valves, they don't talk to the boiler so all they can do is open the flow path but not fire the boiler and run the pump.
I have now looked again at the installed wiring and I believe NOW that the Tado smart thermostat (wired) just connects to the existing wiring centre the builder has put in, that is essentially a big busbar junction box; or to the wireless receiver if this is also a wiring centre; and that through this wiring centre when the thermostat calls the zone valve to open, the zone valve has an internal switch that will send a switched live signal to the boiler to fire it up and run the pump. So via the existing wiring centre, the Tado smart thermostats will both open the zone valves and fire the boiler.
For the UFH, we can either do the same thing - in which case, where does the wireless receiver come in? Or we can use the wireless thermostat for temperature signalling and wire the receiver directly to the UFH manifold (Tado advice). This is then wired back to the zone valve for UFH.
That's as far as I've got, does it sound right?
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