Tado turning heating on in the night - any ideas?

I have 7 rooms/radiators controlled by Tado with a wireless thermostat in my living room room and Tado TRVs providing the temperature input for another 6 rooms. Everything is on the same boiler and radiator loop. I'm in the UK if that makes a difference so it's a very conventional UK pumped hot water radiator system all on a single loop with no fancy zone valves or anything just TRVs controlling individual radiators.

Last night I got caught up in a book so was on the sofa in my living room until 2:00am finishing it. 2 of my rooms are spare bedrooms so are always set to 5C since I don't use them. The other 5 rooms are all set at varying temperatures during the day but all have smart schedules that put them down to 5C at midnight except for my master bedroom that is set to go down to 10C overnight. When I finished my book it occurred to me that it was still very warm so I went and checked my sitting room radiator and it was on full blast at 2:00am and blazing hot.

Now I know that it is strongly recommended by Tado to have a TRV on the radiator in the room with the wireless thermostat in it but I have fancy designer radiators and to fit a TRV I need to replace the radiator completely with the version designed to take a TRV. I might well do at some point because I understand why it is best but for now at least this non-TRV radiator is in the biggest room in my home that is set to the highest temperature of any room anyway (by about 1C) so as TRVs fire up the boiler to keep my other smaller rooms at their set temperatures during the day and evening it is unlikely that the extra kicks of heat into my bigger sitting room will take it too far over temperature, or even over temperature at all, and in my few weeks of Tado ownership this does seem to be the case so for now I'm living with what I have.

At first I thought I might have accidentally set a room temperature higher and left the room set on temperature changes staying in effect until manually cancelled rather than until the next schedule temperature change (I've made that mistake about 3 times so far as I've added rooms/TRVs!) but no, every room was at its expected 5C/10C overnight smart schedule temperature and all rooms were showing current temperatures on the Tado dashboard significantly above their set temperatures. Even the unused and never heated bedrooms were at about 12C and the living room was at 22.5C vs their set temperature of 5C so, as expected, the Tado dashboard showed no heating on any room despite the fact that the boiler was on and pumping out heat at full blast into the un-TRV-d sitting room radiator. The Tado wireless receiver did "know" that the boiler was on because when I went and checked it I could see that the blue heating LED was on so the reason that the boiler was on was because Tado was closing the heating relay in the receiver rather than a short circuit or some other glitch in the boiler itself.

I then looked at the lights on the internet gateway and all 3 were solid white and the Tado app confirmed that there were no "connection lost" or "no remote access" communication issues in my setup so I am now at a complete loss to explain what was going on. This seems an incredibly basic fault so I'm wondering if there might be some faulty hardware in my setup or does Tado sometimes have such "brainstorms"?

As a next obvious step I would have power-cycled my internet gateway and maybe also my wireless receiver in case it was a firmware bug that a reboot might have cleared but it was about 2:15am by then and I didn't want to mess about with it in the dead of night, and it's cold in the UK so I also didn't want to risk ending up in a no-heating situation the following day (today) so I just left it alone.

As I type this it is now 11:00am and the boiler is off so Tado has finally stopped holding down the relay switch when no heating is required and my dashboard is showing every room pretty much dead on their smart schedule target temperatures so sanity seems to have returned. I still need to contact Tado support on another couple of issues so I'll watch what happens overnight tonight and Sunday night before contacting support on Monday to discuss this and the two other issues that I am having but in the meantime I'd be interested in any insights that more experienced users might be able to offer regarding why my Tado setup went crazy last night and whether the behaviour I described above has been encountered before. Anything I can learn hear first might be very helpful for my discussions with Tado support on Monday.


  • I have the opposite issue where tado not switching on the heat, even when trvs calling for it. I'm wondering if you've missed the OFF switch whilst I've missed the ON switch. I wonder if there are issues at Tado on the cloud side?
  • I had this issue until a few days ago (boiler switching on in the night when no demand). I'm sure I have worked out what caused it to switch on but I'm not clear on why. My system (room thermostat and smart TRVs) are set to switch off at 10pm and back on at 6:30am. On two occasions when the system switched on in the night I noticed that the app was showing 'no remote access' for the receiver. Even though it lasted just a few minutes, when the connection was restored the boiler seemed to be driven from the room thermostat, aiming for the last temperature that was set in the thermostat. This setpoint remained all through the night.

    The fix that I put in place, that seems to have worked, was rather than 'switching off' the room thermostat at 10am, I have now set the schedule to reduce the temperature set point to 10 degrees (which of course it won't hit). Since then, the boiler hasn't switched on during the night.

  • sorry, *10pm (last para)

  • Thanks for the replies. My issue seems to be different to yours @Leyther and sadly for me it persists, it happened again last night. My heating seemed to switch everything off OK at midnight and to be sure I went and checked the wireless receiver just after midnight. The blue LED heating light was off and, as expected, all the lights on the boiler showed it as not active. At that point I also checked the Tado app and all rooms had gone to their overnight temperatures, 5C for everywhere except the 10C in the master bedroom. I then went and did an hour or so of reading in my living room. Just after 1:00am I checked (although I already knew because of how hot it was) and the boiler was back on and the living room radiator (one of the few without a TRV) was at full blast.

    The living room is where my wireless thermostat lives and, before the smart schedule for that room turned it down to the overnight 5C temperature at midnight, the last active heating temperature in the smart schedule for the living room had been 21.5C. The actual temperature Tado though that the living room was at at about 1:15am was 23.5C and I'm sure that it was right because it was uncomfortably hot. I think that for my case at least that demonstrates that it's not reverting to the last set temperature on the wireless thermostat (or anywhere else in the system) because there aren't any time blocks in any of my smart schedules that go above 21.5C so letting the temperature get up to 23.5C with the heating still going full blast to try and make it even hotter is totally off the scale.

    I guess I need to raise this with Tado support because there have been at least a couple of other nights since my initial post when it's happened.

    A few nights earlier when it happened I went and power-cycled the wireless receiver unit (by switching on and off the mains isolation switch next to it which also feeds the boiler) and after the wireless receiver rebooted the blue heating LED stayed off and the boiler stayed inactive as I wanted. This was again at about 1:30am and I then went to bed so I can't be sure that Tado didn't fire up my boiler again a few minutes later but the reboot did at least seem to clear the heating-permanently-on state for that night which makes me wonder if I might have a hardware fault in the wireless receiver unit causing it to crash now and then.

    By the way, when you say "rather than 'switching off' the room thermostat at 10am, I have now set the schedule to reduce the temperature set point to 10 degrees" what do you mean by 'switching off' a room? The only way I found to control rooms is via the smart schedule time blocks so when I 'switch off' a room I put a time block into the smart schedule for that room with the temperature set to 5C. Is that what you mean by 'switching off' or is there somewhere else in settings where you can explicitly say don't heat a room at all at certain times?

  • Thanks Julian for your excellent posts on this topic. Did you manage to sort this out or get an answer from Tado support? Last night I had the same or similar occurrence. My smart schedule is set to 14'c overnight in all rooms, including the living room where the thermostat is located. I have Tado TRV's in all bedrooms.

    This morning my wife told me that the heating woke her up during the night - she could hear the radiator valves turning on/off. I slept through it myself. When I checked the temperatures overnight on the app I could see that the heating had turned on when the temperature in the coldest room was about 16'c. This is 2'c above the minimum temperature set, so the heating should have stayed off. Unfortunately, as I was asleep I couldn't check any of the other things that you looked at, for example connection lost or no remote access. Thanks.

  • sdmaino
    sdmaino ✭✭✭
    edited February 2021

    Let me give a try.

    did you set the “early start” feature in the room settings ?

    I am sorry I don’t know the correct word used in the app as my system is not in ENG , I am referring to this option:

    It happened to me that sometimes it started heating too early, could this be your case ?



  • Hi Davide,

    I did not have the early start switched on, so this should not have caused the heating to turn on during the night before 7am.

    Thanks, Steve

  • I’m in the UK using a Vaillant boiler wired by eBus. You have just reminded me that I need to talk to support as I get the same phantom boiler switching on after midnight.

    All heating zones show as above their set point, with no demand from any TRVs. There are no communication issues being reported.

    When I notice it I’ve pressed the “away” mode which stops it, and then after resuming home mode I’ve not noticed it (however I then usually go to bed so who knows)

    The problem I see is that you can check with trvs are calling, yet non have resiults matching the time stamps.
  • I just noticed a few phantom requests for heat lasting a minute when Tado app says no rooms are heating and all rooms are up to temperature

    Since using Opentherm I've noticed lots of smaller requests for heat when rooms are just approaching set points but today I noticed the heating turns on randomly even though no rooms are requesting heat

    Anyone contact Tado support about this?
  • gary333
    gary333 ✭✭
    edited February 2021
    I contacted them about this historically. They said they would need the times and dates so they could check what Tado was doing at the time. They said it had to be by email or chat so they could look into it. They wouldn’t check over the phone.

    It’s one of those things that’s always on my to do, and never gets done. It’s reassuring to know this is happening to others. My evohome was really bad for this, far worse than the Tado. Honeywell could never get to the bottom of it, that’s why I swapped to Tado.
  • Thanks @gary333 I'll note the times and reach out to support for help

    I've noticed the following when using Opentherm:

    1. Tado requests heat
    2. Boiler enables heating mode
    3. Boiler fires up to around 40oC (max on knob is set to 70oC
    4. On the next cycle boiler fires up to higher temperature depending on demand

    I'm not sure why step 3 happens. Almost feels like a test run before the proper cycle.
    I think the phantom request may just be a test cycle. This is just a guess from my observations
  • That is interesting. My boiler is out of the way in my utility room, so I don’t really have ability to watch it (without getting bored straight lol). If I have all the doors open and it’s late, sometimes I notice it due to the noise but mostly I cannot tell so could be doing this far more often.

    The last time I noticed (the other night) my boiler said in its menu Tado was requesting 32oC via eBus. Because the temps are so low, and all the TRVs are off (with only a couple of bypass rads) the boiler is on then off really quickly. My CH was set to 55oC max in the setup screens at the time. When reviewing the usage graphs, none of the devices had requested heat for more than an hour so really random.
  • Just to add. It’s happened again tonight at 11pm.

    -Tado requesting 32oC via eBus with boiler showing 24v dc input being activated (Vaillant installer menu)
    -No zones calling according for heat according to app, with all zones at least 1 degree above set point
    -Heat call lasts for 4 minutes with eBus value returning to 0oC

    I’ve had this happen across the last 3 nights between 11-12pm
  • I have had my boiler turn on randomly twice in the last 2 nights, and I have my schedule set to frost protection overnight, meaning there should be no TRV that is open, and no room should be calling for heat. I have constant connection problems with different devices every day (12 TRVs and a central Thermo).

    My best guess is as yours - if a scheduled time switch occurs while any device was offline or unreachable, the relay switch at the thermostat does not get the message that all devices are set to off.

    I’ve remedied this by telling Siri / HomeKit to once again, turn all the heating off, once I’m able to with all devices accessible in the app. You could also probably do the same by using the “boost” mode, then use the “revert to schedule” option after 10-15 seconds. Both methods ensure every TRV “phones home” to the thermostat and triggers the relay after the safety delay.
  • The logic you mentioned about a random TRV not sending it's message back to say "closed" does seem plausible, however my understanding (and one of the reasons I moved from Evohome to Tado) was that all communication about what to do was controlled by Tado's cloud server so that the in home zone controller didn't become the bottleneck. It would be good if someone with a more technical understanding could let us know how the TRV's opperate.

    For example:

    I was having a similar issue to what you mention with the Honeywell Evohome. I believe what was happening (even though Honeywell could not say for certain) was the controller sent out the command to shut down the TRV. The controller would then report no demand, however this message on screen showing no demand wasn't actually the current state as in the background it would wait for all the TRV's to acknowledge before actually shutting off the request. Honeywell confirmed that only 1 TRV could communicate at once, and thus if you had to shut down 10 or so TRV's the messages could clash and require re-sending over and over. To save power the TRV's would retry, but would only retry at a given interval. This could mean (especially in houses with radio interference) that the message might not get through until quite a long time later. Honeywell advised there is some form of clear command and that after 30-45 minutes the device will just ignore that it hadn't had a request and then shut of the heating request. I was finding that every time I wanted to shut off the whole heating supply the boiler would continue to run for a good 30+ minutes.

    The type of issue I describe above is clearly much worse than what the Tado does, however both scenarios of heating requests with no TRV's open is not a good show as it risks damaged the heating system if you rely on the internal re-circ, or just have a little radiator to dissipate the heat when using massive combi boilers that are all too common in the UK. The Evohome approach to this was even more silly in my mind as it would repeatedly fire the boiler for 30-45 minutes. My Tado does just appear to fire once.

  • @gary333 thanks for the update. Ah my boiler is located in the kitchen so it's much easier for me to monitor. I've not noticed any of these phantom requests recently but it may still be happening without my knowledge

    Good to know that the issue is resolved not as bad as Evohome!