Why does the system ignore the set temperatures?

TadoUser2

Having fitted my system back in June, I am now just beginning to use the system in anger and to fine-tune it to my house.

The system is as follows:

Two Zones each controlled by a Wired Thermostat.

8 x TRVs comprising 6 x Smart version, and 2 x Basic. All but one TRV is bound to the Zone Controllers to call for heat, the last one is set as Passive as its in a room not regularly used.

2 rooms are controlled by Wireless Thermostats and are set correctly as the Measuring Device (I intended to add more Wireless Thermostats, but since finding my issue, I've put this on hold).

Boiler is a Grant Condensing Outdoor Module (Oil). Controller in line is a Horstmann 3 channel set for always-on so Tado controls everything.

Problem:

Last night I looked at the app. Landing was cool at 16.7 degrees. I increased this to 19 degrees on the app. This would heat the landing (the Landing Radiator's Tado TRV uses the Wired Zone Controller as the Measuring Device) and the two bathrooms as they do not have any TRVs attached at all, they are always on and therefore heat passively when any room upstairs calls for heat. 15 minutes later I went upstairs and the Landing Radiator (and the two bathrooms) were stone cold. I manually increased the Wired Thermostat to 21 degrees, nothing. I increased to the maximum and it finally turned on and began heating the rads.

Secondly I have set the heat to come on in Zone 1 (downstairs) at 0630hrs. The temperature is set to 18.5 in the Living Room, (warm enough for us), other rooms are set lower. The boiler fired and heated correctly. One by one the TRVs turned off the heat leaving the Living Room heating (confirmed on the app. The app reported the Living Room at 18.8 but the Zone 1 Thermostat kept turning the boiler on to heat (I heard it click on). I had to turn it off manually as the system was unnecessarily using oil.

Question:

Have I set something wrong? I can't understand why the system seems to mostly be ignoring the temperatures I have set on the TRVs and the various Thermostats. AFAIK I have set the Measuring Devices and Zone Controllers correctly and have double-checked this.

I'd really like this to be more of a set and forget system, but currently I seem to be manually overriding it way too much. Is there an AI something going on in the background that I could turn off perhaps?

Any thoughts welcome. I am happy to check settings and try anything to get my system to respond according to my chosen set temperatures.

Thanks in advance.

TadoUser2

Are there really no recommendations? Have I messed up buying Tado? Should I just give up and send it all back?

pcone

It certainly sounds like it's not set up quite right.
What happens when the upstairs thermostat is triggered? Does that fire up the boiler, or just open the valve to allow water to flow around the upstairs radiators? You might need to get Tado customer service to check the configuration for you.
For the downstairs issue, Tado will fire the boiler if the current temperature is above the set temperature, but falling rapidly. This might be what's happening in this case.
I've been very happy with my Tado - it's generally able to maintain the temperature to +/- 0.1C of the set temperature, and saved me ~30% compared to my previous gas usage.

TadoUser2

Thanks pcone, I appreciate your suggestions.

Yes, once I had set the upstairs thermostat to 25 degrees it triggers the boiler. That thermostat is a wired one that replaced a Drayton wheel thermostat. The thermostat appears to be functioning correctly, except for needing to be set at maximum before it is heard to click on.

I understand the downstairs thermostat could carry on heating if it is detecting a rapid temperature reduction, it makes sense this could happen. But this is unlikely to be the case for me as I have a B1 rated house that holds heat really well, in fact the heating is only on for a hour morning and evening.

Compared to your system's ability to maintain temperatures as well as it does, it suggests my system is either set up wrong, or is faulty. As I have looked at the setup closely and had two other people check my setup, just today, and pronounce it set up perfectly, I think I must assume I have a faulty wall thermostat.

Thanks again for your advice. If I hear nothing from Tado I think I will order another wired thermostat from Amazon and see if that changes anything. If not, perhaps its just not suited to my particular house, boiler, system or all three.