Tado & Vallient Combi Boiler (what should i get)

zane99

Hi all

Having a new heating system fitted in Jan consisting of:

- Vallient EcoTEC Plus Combi Boiler
- Wet Unfloor Heating downstairs (2 zones)
- Rads upstairs (3rd zone)

Would like to use Tado but wow is it confusing trying to work out what id need to get haha.

All i want to really do is control each zone from an app. Smart Rad valves are a nice to have rather than must have.

Any advice appreciated.

policywonk

Need to take this forward in steps.

Some questions first.

1. You have a Vallient EcoTec Plus Combi. Tado can control this boiler in both dumb mode (on-off, what most engineers call relay mode, what Tado call R01 mode) and in digital mode (Tado refers to it as type D07, connected to the BUS connector). The latter digital mode improves efficiency of the boiler's use.
   1. What exact model of boiler is it? There are over two dozen with slightly different configurations. Need to clarify.
2. You have two UFH zones.
   1. Are they individually actuated by a motorised valve?
   2. Are they individually managed by a dedicated wiring centre? Can be a Heatmiser, Salus, something else.
   3. Normally there is a wired thermostat controlling UFH supply to each room, and these trigger, via the UFH wiring centre, the actuators to open and supply that room with heat.
      1. How many thermostats are there? What brand/model?
      2. Are they wireless, or controlling the UFH manifold with wired connections?
3. You have Rads upstairs.
   1. How many? Do they all have TRVs?
   2. How many bedrooms?
   3. Does your home have stone walls or is it over 200sqm in size?
   4. Have you had any problems with wireless access in your home in the past? It is often affected by the density of walls.
4. What exact model of programmer do you presently have? Is it built into the the boiler, or somewhere else?

You will need all this information before deciding on what to buy, and some of this information has to be passed onto Tado so they give you the correct instructions for the implementation. Come back and we'll help. Most of us are just end users, but we've been around the block a few times.

zane99

Wow thanks so much, ill speak with the heating engineer and get these answers ASAP

kramerica

I too have the same questions.

I have a Valiant Ecotec plus 838 combi

3 UFH heating zones on the ground floor with 3 program thermostat

on the 1st floor, another manual thermostat which has 4 rads and towel rack link.

on the 2nd floor it's another manual thermostat which has 3 rads and a towel rack

1st and 2nd floor are using the honeywell.

The plan is to replace these 2 manual thermostat. Would the v3 wired version or the wireless v3 with hotwater be more suitsuitable? I only have a combi.

No issues with wifi as I use a mesh system.

All rads have manual TRV

policywonk

@kramerica Many of the solutions will be the same but you may need a dedicated thread.

For the interim these are my thoughts:

1. Identify and replace all the thermostats (Honeywell and Heatmiser) with Tado wired ones. Your engineer will understand that the wiring is crucial to triggering the UFH zones.
2. The zone for the rads will need a wired smart thermostat to trigger the zone valve for the radiator zone.
3. If you then want each TRV on the radiators to have a role, you can later buy smart TRVs from Tado which can then instruct the wired stat fitted in (2) to follow their lead. The wired stat will still manage the boiler.
4. You need to get hold of the installation guide for your boiler. It will provide you with the wiring information.
5. Then get in touch with Tado via the app, explain that you have this specific combi boiler and you want to manage it in digitla mode. It has 3 UFH zones with Heatmiser wired thermostats, one radiator zone with a wired thermostast. Ask them for a proper plan to move from what you have presently to a Tado setting. They should respond within a week.
6. You will need to study the final wiring centre thats close to the boiler if you intend to do the wiring yourself. Are you comfortable doing it? A sparkie can get this done in less than a day.
7. Now if you hit a glitch with any of this, get stuck, come back here and we'll help.

kramerica

Thank you very much for your reply. I think I will just start with replacing the 2 Honeywell thermostat first. Looks like the easiest. I will leave the UFH alone for now since it has a programmable thermostat. So I will need two separate wired thermostats for the 1st and 2nd floor? Will it require 2 bridges? or can both thermostats connect to 1 bridge? Or can 1 wired therostat control both floors?

policywonk

@kramerica. Not quite. The thermostats arent acting as relays in this instance. Even though their wired side turn on the valves for UFH, they also communicate with the main zone controller which I presume handles the Radiator zone and boiler together. It will depend on how your S Plan was wired.

Every zone is independently calls for heat. If any calls for heat, the boiler needs to have a route to be told to turn on and at the right throttle level. The way Tado wired stats work, would summarise like this:

• Zone valves (for UFH, the radiator zone) are instructed to open when there is a call for heat initiated by the thermostat- usually a wired thermostat.
• Tado wired thermostats do that, but at the same time, wirelessly, they also talk with the specific zone controller that directly talks to the boiler.
• In this case your boiler happens to respond to digital requests, so, if you want to operate it in that mode, which saves money, one needs to standardise it all :
  • A Tado wired thermostat is installed replacing every existing wired thermostat.
  • With Tado's instructions, one will be wired directly into your boiler, via the EBUS and modulate demand through that interface.
  • The others still drive your UFH zone valves, but wirelessly link to the one that engages the Ebus wires and thus affect the modulation process.
• You only need one internet bridge.
• However you need to double check the main wiring centre's logic on how the final call for heat is passed onto the boiler - one of the thermostat's has that role.
• Hence it is important to get Tado to send you the specific instructions to install this. It isnt a simple swap, will take some thinking and you need to follow the procedure carefully, because the boiler must go into a digitallly controlled mode- and it must be placed into that mode correctly.