I raised the same issue with Tado Support on Monday as mine does the same. Not had a response back yet.
Would people mind putting what protocol they are using and boiler type so it becomes clearer if this is related to a specific setup.
Thank you for opening this topic.
At this time, there is no systemic issue with the tado system that we are aware of.
The heating coming on at night can have a variety of reasons, some of them tado related, others related to the heating system or faulty wiring.
I will give you some hints so you can continue with your troubleshooting:
I hope these steps can help you to troubleshoot the described issues.
Edit: My previous comment just got removed and requires approval, not sure why...
I wrote that previous comment on mobile so I couldn't attach a graph - but just to show you how bad the connection is, I've attached it below. I've rotated and swapped multiple different TRVs at this radiator multiple times with others. It's only 3m away from the Bridge, with line-of-sight. There are TRVs that go through 2 thick concrete walls up to 10m away that are more reliable and don't drop connection.
Device is only in use for around 8 weeks, all TRVs installed at the same time with the provided batteries. All show battery levels as full.
Maybe I've just got a bunch of lemons?
Come to think of it - last night I specifically had HomeKit turn all heating to OFF rather than a low temperature. This was the first time I've done so while some TRVs have been offline in weeks. When I was walking around the house to turn TRVs manually off, some of the TRVs still had the human (Away) icon illuminated, meaning they'd never correctly triggered I'd come home at all. This was in rooms where I have 2 tado TRVs. I've previously done what @Steve_1 did - switch to away mode and back manually to solve this issue too, though I forgot to try it last night in my maddened, half-asleep state. Not sure if your issue stems from Bridge reliability, but I wouldn't be shocked if so.
@cbd20 That might have been my own comment you're referring to :)
Unfortunately I can't really find a Bridge position that will work unless:
Given I had a 2-week period of near-perfect reliability across all 8 rooms and 12 TRVs, I'm struggling to work out how a router reboot could have caused connection issues to flare up again. If we were given some kind of ability to read and measure exact signal levels, we'd have some better idea of what works and what doesn't. As it currently stands, we're expected to calculate millions of permutations of location, angle, and height ourselves. Working out if it works takes days to test, and more time just spent looking at graphs. The more rooms and TRVs you have, the more frustrating this process becomes.
Something I discovered by absolute chance today however. I have early start, window detection and anything "smart" completely switched off. I had a window open to air the room, and the temperature was dropping. Although I've set that room to heat at 15º, the boiler turned on and the room called for heat at a tado reading of 16.3º. Logic would dictate that if I've disabled window-open detection, early start, and set a room temperature of 15º, that indicates I do not want to heat the room at any other temperature threshold! I don't think tado accounts for this, or makes it clear enough anywhere that this is the expected behaviour if you've turned off all early start options. I know tado thinks they're smart by adding in logic to anticipate heating demands, but if you've got those switched off, it should respect those parameters. Even if that logic is not possible to completely disable/remove by the end-user, surely you would consider the edge-case of time of day and duration the heating was off? If I'm home for hours, and the heating's off, why on earth would I need the heating suddenly on at 2am? I think tado is trying to anticipate a bedroom going too cold overnight, maybe saw a drop in temperature somewhere, and decided it had dropped quickly enough to begin heating, even if the temperature was way above the minimum set in the time schedule. Just speculation, someone from tado would have to clarify if disabling any pre-heating options actually disables that behaviour entirely.
Thinking that might have been the issue, I checked the graphs for all devices at the time I walked to the toilet. 2 TRVs were offline so they have no heating data, the other 10 show the temperature was at least 3-4º above my minimum of 15º (18.5-19º). The room I would've caused the most temperature difference in (bathroom) was still 2.5º above the minimum set overnight. I was only in there for 30 seconds so I can't imagine that movement triggered the boiler. I've ruled that threshold logic issue/bug out for now. For now I've set my minimum temp down to 12º instead of 15º again (I did this weeks ago), just to keep whatever "magic" tado thinks it's doing out of my house.
The investigation continues…
@cbd20 According to https://support.tado.com/en/articles/3387308-how-does-the-open-window-detection-skill-work and what I see in the app, there's no indication that disabling open-window detection has the side-effect of enabling early pre-heating, when that is also disabled everywhere. It's meant to turn heating off and stop it from turning on (when enabled), not turn the heating on, so whatever in-built logic there is here seems hidden from the user, which I find mildly irritating.
Last night something bizarre occurred, which I'm going to try and reproduce again tonight. All my rooms have their final scheduled time block end at 23.30 and switch down to 12º. Last night, I turned all heating off a little earlier, at 23.10. I was in the living room at the time (where the smart thermostat is mounted) and heard it click the relay switch OFF. All good so far. 20 minutes later at 23.30, when my time schedule and all devices should go from OFF to 12º (still too low for any room to call for heat, they were all around 22-25º at that time), the thermostat relay switched back and turned the boiler and heating ON! I had to go back into the tado app and turn all devices on (boost), then turn them all off again, for the relay switch to flip back to an off state.
I'm starting to consider that because I use a HomeBridge which allows HomeKit-issued commands to remain in "Automatic" mode (rather than in eternal Manual Control which is tado's default HomeKit implementation), that the Smart Thermostat is in a flipped state, or doesn't even know what state it's actually in. This is rather odd, but I'm starting to consider that tado's logic doesn't account for this, even though all I've done is the equivalent of going to each TRV and turned them to OFF manually, with my room settings set to "Until next time block".
This doesn't explain the random turning on of the boiler at 2am the other night, but I did turn off my heating earlier that night. It seems there might be an issue with me turning heating to OFF and returning to the next time block, in combination with devices going online/offline during the night.
@cbd20 I'd generally agree with you there, but after inspecting the graphs further, the logic seems to indicate this is additional logic to the handling of a "window open" event. It's possible the graphs are lying and don't indicate the actual state of the boiler (ie. it doesn't verify the relay switch position and whether your boiler is actually on or not at the Thermostat). You can see my annotated graph. Normally open-window detection occurs within 1-2 minutes of a sudden drop in temperature (when I had it enabled), but this was a 46 minute time period, with a drop of 5.9º, with 2 requests for heat that didn't cause any boiler operation. It might be that multiple requests for heat over an extended period of time need to occur to avoid false positives and turning the boiler on and off too often.
In any case, setting my room temperature to 12º as opposed to 15º should hopefully avoid this wasteful situation, as it's much further away than any threshold values the tado devices are programmed with. We have good insulation in our homes here, you can see on the left side of the graph that my rooms don't generally go below 16.2º with no heating at all. This heating behaviour is therefore not as "smart" in my particular instance and why I'm annoyed it tried to second-guess my desired 15º minimum temperature. You can read on the German forum some other issues with tado and the German tradition of lüften (which is what I was doing at the time).
Thanks to Jurian for providing some ideas for positioning the internet bridge. The installation guides should be updated to explain these things. I imagine that a lot of people, like me, just connected their bridge close to the internet router and ended up having lots of problems, like me.
I offered to be part of Tado lab's research effort to follow people installing their equipment. Unfortunately, I never got any further information from them. The internet bridge positioning problem is potentially the biggest cause of issues.
I've had my heating off for the last 2 weeks due to warmer temperatures, but the last days have been cold once again, so I turned on tado for the first time in 2 weeks... and lo-and-behold, after turning off the heating a little earlier than my usual scheduled reduced temp mode, the boiler fired up last night yet again for no apparent reason at 1.30am.
I ended up walking around the apartment for 20 minutes half-asleep trying to get it to stop heating. See attached screenshot. 19.2º, and yet "heating" with fully opened valves to 12.0º. This room has the Smart Thermostat, plus 2 TRVs. 1 TRV was still stuck thinking I was in away mode (showed the human symbol), yet my away mode temperature is 12º anyway. The other TRV was stuck at 23º, despite previously being set to OFF. None of the 3 devices showed connection issues in the tado app. The only way to get everything to stop was to reboot the main Thermostat and 2 TRVs in this room. Nothing else (Bridge reboot, various Home/Away/OFF/temperature settings) would work.
How can this be explained? How can the Smart Thermostat or TRV not realise it's heating 7.2º above the target temperature, when it has complete connection to the Bridge? What combination or permutation of logic could possibly make it calculate a random call for heat with such sensor data available to it? As this room as 3 tado devices, the graphs are not possible for me to individually extract data and see what exactly happened to cause a sole TRV to jump from OFF to 23º during the middle of the night (which is the only conclusion I can come up with).
FWIW this room (living room) is the same room with the Bridge, and it has complete line-of-sight to all 3 devices. I gave up after many weeks of trying to find a reliable Bridge position for all 12 TRVs - I'm looking forward to the warmer days so I can forget about tado's reliability for a good 6 months or so...
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