2 Zone Heating with Combi Boilder

inderjangid

Hi All !

I am recently moved to a new build, which has a combi boiler. There are 2 heating zones, one on ground floor, and the other one on the first floor. I want to put Smart Ratidators to control heating for each radiator individually.

I am newbiee here… don't know lot of stuff. Can someone help me with all stuff I need to buy to setup smart radiator thermostat ? Will putting Smart Radiator Thermostat on my rads will help me to control them each Radiator? Or do I need to buy Wireless Smart Thermostat as well ?

Emcee

Hello @inderjangid and @wiimixer,

If this is your first time using tado° (meaning, you're starting 'from scratch'), your best bet is to get a 'Starter Kit' and add-on devices based on your individual needs. This is because 'Starter Kits' include an Internet Bridge, which is (in most cases) needed for devices to communicate with each other.

( I say 'in most cases' because tado° has recently released a new line of products called tado° X. These don't necessarily need a bridge due to the fact they work with Thread and Matter technology. However, I don't want to get too ahead of myself here because these are a lot of details that you might find more confusing than helpful. Let's just assume that, for you guys, an Internet Bridge is needed).

Now, you have decide whether you want tado° X or V3+. These are 2 disctinct generations that are not compatible. tado° X is well suited for people with large homes who also want to benefit from the new Thread and Matter technology to optimize their third party smart home systems. V3+ is our tried and true generation that has been on the market since 2019 and works for 'normal' sized homes and can also have some integrations with third party smart home systems.

Once you decide which generation you want, you can contact tado° support via live chat and check your current heating set-up's compatibility with tado°. Support can also provide you a list of devices to purchase to replace your current thermostats. Make sure to perform this compatibility check before purchase.

wiimixer

We have the same scenario: new build (though 5 years old now), combo boiler, two heating zones.

Someone might have a different/better solution, but our tado setup involves TWO room stats (one bedroom, one hallway) then four TRVs for principle rooms - excluding the bedroom with the room stat.

This way we’re still able to control the secondary (bedroom) circuit independently.

Happy to answer any Qs!

inderjangid

So I need below -

Wireless Smart Thermostat Starter Kit V3+ to get 1 Wireless Temperature Sensor, Wireless Receiver and Internet Bridge

One additional Temperature Sensor

Smart Radiator Thermostat for each radiator

Current wired thermostats will replaced by Wireless Temperature Sensor or wired Smart Thermostat in both zone.

Hope my understanding is correct ?

eezytiger

EDIT : If I misunderstand the meaning of a "two zone system" then I apologise for the following waffle and you can ignore anything I've written. But, if I understand correctly…

If I may chime in, with a system like Tado and a combi boiler, I'm not sure there is any need for a "two zone system" and I'm not even sure that it makes sense as a concept.

There is only one boiler and one set of pipework. Each radiator with an SRT can act individually as a "zone". Each one can have a set temperature, on a unique schedule, and can request the boiler to come on at any time.

Certainly you could configure Tado to operate in a sort of upstairs/downstairs mode, but you don't need anything out of the ordinary to accomplish it. You just schedule the downstairs valves to a higher temperature during the day and lower at night and whatever you like for the upstairs, bearing in mind that hot air rises and cold air descends, so you might not want the upstairs fully off during the day. Not least because cold rooms will mean cold beds, floors, walls etc with discomfort and condensation to think about. Thus, upstairs set to 18C 24x7 (apart from the bathroom, perhaps) and downstairs varied to taste.

But two zones? It's not really a thing, is it? Certainly not in my home. One boiler, one smart wired thermostat and bypass radiator in the hall, one bridge and eight SRTs for the other eight radiators and rooms. I can have anything up to nine "zones" if I want to, one per room, so where does two zones come in? I don't think Tado has that constraint and I'm not sure why you'd want to go out of your way to emulate it.

But there are many ways to configure Tado. For example, in my house it is only the lounge that can fire the boiler when it needs heat. That is my choice, very deliberately. It is set to 16C overnight and 20C during the day. Other rooms are configured as "independent" which means that they cannot force the boiler to fire and will only receive heat when the lounge wants it. These rooms are set to 20C day and night. This sets a high limit of 20C, but it is not a target. They might reach it. They might not. Either way they help heat the whole house during the day, preventing drafts and thermal anomalies and they cool naturally along with the lounge overnight.

So, arguably, I'm using a single zone system and it works perfectly for the whole house. It also helps with boiler efficiency too.

ludwigrh70

Hello!

My apologies to the OP for butting in but I have a similar situation and I found @eezytiger 's answer to be something that can work for me and I just need a few clarifications.

Some background: I live in a 2-storey house and I am using a V3 with a wireless Smart Thermostat. On the ground floor there is an open plan 70 sqm living/dining/kitchen with two radiators with TRVs and a bathroom with its own radiator and a TRV. Upstairs are 3 bedrooms each with a radiator with TRVs and a bathroom also with its own radiator with a TRV. The wireless Smart Thermostat is in the living room.

I want to heat the upstairs rooms 24/7 and the ground floor only between 8:00 AM - 10:00 PM, but currently I am unable to, so I am thinking of moving the wireless Smart Thermostat upstairs and replacing the TRVs of the radiators on the ground floor with SRTs.

My idea is, I can set the SRTs to close the valves of the radiators on the ground floor between 10:00 PM - 8:00 AM, but still keep heating the rooms upstairs.

Can I save heating money by switching off the radiators in the 70 sqm room in the evenings even though the boiler will be on to heat the rooms upstairs?

Will the SRTs on the radiators on the ground floor be able to fire the boiler in case it needs to reach its target temperature even if the target temperature on the wireless Smart Temperature upstairs has already been reached?

eezytiger

@ludwigrh70 Each Tado SRT can be linked to the zone controller, which is responsible for firing the boiler. Alternatively an SRT can be configured as "independent". An independent SRT has no control over the boiler, but it can open and close to a schedule to set a temperature limit (rather than a temperature target) at which point it will start to close.

Any SRT that remains linked to the zone controller is able to make the boiler fire, regardless of the condition of the primary wireless smart thermostat. If heat is needed, "ask and ye shall receive".

But.... You should not have an SRT/TRV fitted to every single radiator. There should always be at least one radiator that remains "open" and able to pass water. Otherwise you could find a situation where the boiler is on, with pump running, but every radiator closed off. Not cool.

Normally this "bypass" radiator will be in the room with the primary thermostat. If you move your wireless smart thermostat sensor to another room or floor then consider how this might affect boiler operation and water flow.

But, yes, in principle you can achieve what you want.

As for saving money by turning radiators/room off, probably the answer is yes. But note the energy required to raise a room temperature by several degrees vs keeping it ticking along at a lower temp and only having to rise a few degrees. Turning off downstairs completely might not be optimum, especially considering humidity from bathroom and cooking and potential for damp. There are many factors to consider including ventilation, insulation, external temperatures/wind etc. How quickly do the rooms cool? How quickly do they heat? It is common to reduce temperatures a few degrees rather than turning off completely.

ludwigrh70

@eezytiger Thank you very much! After 10 years of using Tado and trying to find a solution to my problem and getting confused with heating zones, your answer to the OPs question and to mine has finally given me a solution.

Sorry if I wasn't clear when I wrote that I want to turn off the radiators. In fact, I meant that I want to lower the temperature from 21C to 18C between 10:00 PM - 8:00 AM.

From 21C at around midnight, the temperature goes to 18.5C at around 7:00 AM. It then takes about 45 minutes to go back to 21C. Are those good figures?

I replaced the TRVs with SRVs of the two radiators in the living/dining/kitchen and moved the wireless Smart Thermostat upstairs. I did not replace the TRVs of the radiators upstairs and they are all open.

Thanks a lot again!