Using Tado in only 1 zone

RedScot

Current setup

3 floors, each with a Honeywell CM707 wired thermostat. Also Honeywell ST9100C controller for hot water.

Unfortunately the thermostat on the 2nd floor is in the hottest room, sunny and above the boiler, so the temp has to be set too high if the other rooms are to get hot.

I would like to replace the CM707 thermostat, just on 2nd floor, and add smart TRVs in each room on that floor. There are 6 radiators on the 2nd floor.

Is this possible with Tado? If so, what kit is required?

wateroakley

Hello @RedScot Welcome. Lots of good information from @policywonk

Options: I've tried to distill the options for your second floor.

1. Option 1. Tado wired starter kit. One wireless temperature sensor. Fit the wireless sensor in the coldest room. Keep the dumb TRVs. If the room with the wired thermosat does not have a TRV on the rad(s) you may need to wind down the lockshield to balance the heat. About £175.
2. Option 2. Tado wired starter kit. Six TRVs. Temperature in every room is individually controllable. About £350.
3. Option 3. Tado wireless starter kit. Kit includes one wireless temperature sensor, fit in the coldest room. Keep the dumb TRVs. Minimum kit list and cheapest price option. Bonus: the receiver can control the hot water. £85.
4. Option 4. Tado wireless starter kit. Six TRVs. Temperature in every room is individually controllable. Bonus: the receiver can control the hot water. About £350.
5. Option 5. If you find the TRV temperature meaurement is affected by furniture (e.g. beds) you can add a wireless sensor. £90.

Budget ££numbers are for V3+. I'd advise to buy the devices from a recognised seller with an easy returns policy and avoid internet marketplaces.

You should think about where to mount the Internet Dongle (preferably in the centre of the second floor) that the devices will connect to. Our rellie uses cheap wifi extender (with an ethernet port) on the first floor of their 3-storey Edwardian Villa to connect the dongle. Allow about £20 for this.

User Suggestion: Option 4.

If your budget is tight, Option 3 and add as many TRVs as your budget allows. FYI, our ROI in 2022 was 9 months, others say 24-36 months.

EDIT: If you have a very large home, connectivity with the single V3+ internet dongle is an issue for some users. You may wish to consider Tado X, it will handle multiple Matter/Thread internet dongles.

Results: These are our results from February 2022 by micro-managing the heating. No promises that anyone else can achieve the same.

policywonk

Hi.
Questions.
1 Is there a dedicated two port motorised valve for each floor? Need to understand whether each thermostat only controls one floor as a dedicated zone, or whether they are all wired in parallel forcing the boiler to produce heat when any call for it. The latter would be unusual and wasteful. If the former it helps to clarify your options.
2. Am assuming that you have a dedicated motorised zone valve for each floor, and that all three programmers are wired into a wiring centre which handles all the decisions to call for heat. Is that valid?
3. Is your boiler capable of being controlled digitally. If so, then it operates much more efficiently and saves money. If it is, it is best to switch all controls to the Tado environment that gives you that benefit. If your boiler is only switched in dumb on-off modes then your plan to have Tado only on one floor is viable.
4. Do you have thermostatic radiator valves on most radiators, ie on all floors? This is the fastest way to overcome the imbalance in thermal output needs. Whether you use Tado TRVs on the other floors or just mechanical ones it will help, lots. Using Tado TRVs saved us enough in heating costs to pay back within 3 years in a 11 bedroom rescue centre.
We are, most of us, end users who aren't trying to pitch Tado products, just helping. others to get things right.

Come back and we'll help

RedScot

1. Yes there are valves for each floor
2. Don't know the answer to that one.
3. Yes, I think.
4. Yes, on all radiators except the rooms with the thermostats

The major problem is that the 2nd floor room, with the thermostat, normally reaches 20C when the other rooms are about 16C. This is why I thought about just changing 1 floor as the other 2 are fine.

I really want the other bedrooms to continue heating until they are at 20C as well.

policywonk

The fact that your boiler is digitally control-capable suggests that this isnt simple:

1. At full tilt, when all three floors are calling for heat, the balance of allocation of central heating flow needs to be readjusted. the best solution is to swap all existing wired stats with Tado wired stats first - on all floors.
2. However the imbalance between the radiators needs to be addressed first. This video gives the logic.
   1. Take all the TRVs off, place your room stats at max
   2. Dash to ONE radiator on EACH floor, furthest away from the boiler, and check the pace at which they've heated. Balance them until all three heat at the same place.
   3. Repeat (b) for the other radiators on the same floor, so that they all heat at exactly the same pace.
   4. Put the TRVs back on, wall stats back to normal
   5. Leave it for a day and then repeat the process, fine tuning the balance.
   6. Leave it for a week, repeat the process. This third pass should have ensured that with the boiler pumping at full chat, the radiators respond evenly.
3. Now if in this balanced state you still have problems, check the Central Heating pump setting, and push it up a notch if thats available.
4. Once thats done, now that you've ensured that the distribution of heat (without TRVs) is correct, you'll be able to ensure that with TRVs your house changes temperature efficiently.
5. Now's the time to consider replacing all your wall stats with wired Smart Tado Stats, because without all of them set to make use of your boiler's digital mode, it will be stuck with working in dumb mode.
   1. You'll need to study your existing wall stat boiler's installation guide before taking this step. If it helps, bring back your boiler exact model id.
   2. Also consider that Tado wired wall stats are not portable. They will register the room temperature where they are located and turn on the motorised valves as needed, whilst also instructing the boiler.

Hope this makes sense. Come back if you need clarification.

RedScot

Thanks, a lot of info there.

It would be extremely expensive to replace everything. so that is a no go.

I'm not sure that the issue is with an imbalance in the radiators. The room with the thermostat is just a warmer room, even with no heating on it is 4-5 degrees warmer than the other rooms.

I may see if I can reduce the flow to the radiator in that room.

RedScot

Thanks for all your advice, I'll look at option 2.

I don't need the hot water control and the wired option should be a simple replacement