Tado keeps turning on/off the boiler all the time

I have a temperature sensor with smart thermostat and 3 other smart thermostats in 3 different rooms. At night I leave 2 of them around 18 degrees and one at 20 degree. My bill last 10days been around £200, what I see is different tado thermostats and sensor turning the boiler on even for 0.1 degree difference in set temperature, since there are 4 rooms and each have different thermal loss properties, say one room loses 0.1 degree now , boiler turns on, in 5 mins another room looses 0.1 degree, tado turns on the boiler again, then for other rooms. Like this boiler never stops running. This really inefficient, unnecessary and I really regret getting these smart thermostats. I think it will be much better to let the temperature fall by some degree noticeable (who can notice 0.1 degree difference )then turns the boiler on or there should be a settings for users to configure it.

Tado, how can I stop this madness? I think I better go back to normal TRVs and return the dumb thermostats of tado?


  • Our circulating pump runs even when all heating is off. TADO “chat” advisor seems unaware of a pump in a CH system & keeps asking about our “heat pump” as in ground or air source. I keep explaining & we go round again. We need to find a way to stop the central heating pump circulating unnecessarily when heating is off but cannot get any sense out of TADO. Any suggestions?
  • rafm5
    rafm5 | Moderator

    Have you recently changed anything in your configuration, like the flow temperature?

  • No we recently moved in the property and just fitted tado 15 days ago. It does sound like Tado dont know how their products been used / target customers...

  • On my S-plan system, the pump only runs when the CH and/or HW relays in the Extension Kit close. This then opens the appropriate valve which in turn makes the pump run. .

    Are you sure you've wired up your installation correctly? Perhaps you could provide some more detail on the installation you've done i.e.

    • type of system
    • what tado kit you've installed
    • photos or before and after wiring

    There's plenty of folk on here who may be able to assist you since tado aren't understanding your issue

  • Hi @davidlyall sorry for the late reply. I was basically collecting information on this issue. Here is my finds and understanding.

    I have configured tado to maintain certain temperature in each rooms. Depending on how often the temperature drops, tado is trying to maintain the target temperature. This is expected. For even a 0.1 degree drop , tado trys to top it up, here is the problem. This makes boiler go on and off lots and lots of time, my average boiler time on tado is 16 hrs / 130 kWh at the rate of 10.54p more than £13 a day.

    After reading many threads in this forum, found that in EU tado supports OpenTherm protocol, by which it can ask the boiler to run on lower energy, so to top up 0.1 degree boiler doesn't have to use the full gas. In UK they stopped supporting OpenTherm on wireless thermostats. This is problem number 1. However UKs old tado Extension Kit seems to have support for OpenTherm. I managed to get hold of that kit but there is one more problem.

    But I have another problem that my boiler Worcester greenstar 24ri, doesn't support modulation. Confirmed this with Bosch team.

    So I need to workout a schedule for my heating that my boiler doesnt come on to heat 0.1 degrees every 10 mins or so, instead may be every half hour or one our come on and heat up by 1 degree or something.. May be I dont need tado for this.. an old timer based thermostat would do... I have few days to return all 9 smart thermostats (30 day return policy) and sell wireless sensor on ebay...

  • Hi, I have been having the exact same issue…Tado seems to be kicking the boiler on all time. Did you figure that it was because you didn’t have opentherm that it was costing you so much?
  • royi
    edited January 16
    I've just tested my system and having the same issue. I have the Wireless thermostat. This isn't good for the boiler.

    Work round - Once the temperature is reached I lower the temperature, putting the boiler in standby. I know it's not ideal.

    @NeoXpress it seems like you have identified a bug.
  • Montage
    Montage ✭✭✭

    If it's not in digital bus mode, Tado will follow the fairly normal TPI thermostat approach of mimicking modulation by turning the boiler on X times an hour.

    This approach will best suit homes with a standard layout, with one zone (one device calls for heat) and a modern condensing boiler.

    Increasing the number of devices that can call for heat and/or removing (available) rads from the circuit will negate efficiency benefits.

  • Sorry @NeoXpress . Just back into the forums after a while away

    So, just to clarify, you have a wireless receiver and a number of TRVs? You're finding that even if the temp drops by a small amount below set temp, the system is kicking in the heating?

    That's certainly not my experience although I have the older extension kit (still on relay mode) with 7 TRVs (2 set as independent and the other 5 with the EK as zone controller).

    I find that if a room temp starts dropping, Tado will open a valve but won't necessarily start the boiler until the temp drops further or another room also demands heat. I actually find that a room can be allowed to drop by half a degree below set temp if no other rooms are demanding heat. It also cuts off before reaching set temp as there's enough energy left in the rad to continue heating the room. This appears to reduce cycling of the system quite well

    Are you sure it's Tado causing the boiler to cycle? Do you hear the relay click in the wireless receiver each time a room calls for heat? I'd be surprised if Tado is cycling that much. Could it be that the boiler is cutting the gas when the circulating water reaches the set temp e.g. 70c and then clicking back in again when it drops by say 10c?

  • I seem to have same problem.

    Thermostat demanding heat for 0.1 below set temp and firing boiler but not opening rad valve to allow hot water in

  • gary333
    gary333 ✭✭✭
    What boiler you got? With Vaillants you can change the anti cycling time to prevent the request from firing the boiler and thus chose maximum time it can fire per hour.

    On Evohome you could user select maximum times boiler to fire in an hour. Default was 6.
  • I have (had) the same issue. 7 SRTs across 5 rooms, Tado wired thermostat connected to the boiler via OpenTherm. My boiler was cycling a lot, like constantly.
    After I removed all the SRTs, but kept the wired Tado thermostat, everything started to work properly, cycling is really rare and modulation is done correctly.
    I have spent a lot of time on figuring out why installing the SRTs resulting the boiler to cycle but could not figure out. Maybe it is related to how many radiator valves are open at a given moment… After I watched the Heat Geeks video about why “not to zone your house” maybe anyway it is not a good idea to control the temperature room by room.

    Now I am performing some last tests before sending backs all the SRTs and asking for a refund.
  • @Valaki1234 that's interesting.

    were your tado radiator valves set to independent or were they assigned to the zone controller?

    my boiler is cycling all day in these low temps, i thought it was normal in these conditions and using opentherm?

    i use to have mine rooms zoned, but now just have one room set to a zone controller, all the rest radiator valves are set to independent.

  • When I had my SRVs set to be able to call for heat they were doing it all the time. Turn them to independent. It then works more like Tado did when they worked properly as they hadn't complicated themselves with radiator valve meddling. It usually tops it up every so often but if that isn't enough it will run for longer. It doesn't generally keep coming on and going off all the time.

    Also the more steps you have in temperature changes the more it seems to lead to messing about. I have a set back over night temperature and one day temperature from in the morning to bedtime now. Rooms are left on fixed temperatures all day. If you use the home/away function then it will pick a set back temperature if everyone is out.

  • @srichards
    You've more or less gone back to a fairly basic system of control.......I've ended up doing something very similar..... I now have only 1 device that can call for heat and all other rooms/devices are set as INDEPENDENT. This gives little to no cycling (in this current cold spell).
  • @Ervcrt100

    I tried to use them as independent, but the results were the same: cycling. Maybe if I gave more time for this setup (tried it over ~2 days) it would have been improved, but just got annoyed and replaced all the SRTs with dumb ones.

    Currently I have a similar setup as @srichards explained, 20C during night, 21C during the day, 20C when noone is at home. I can achive this behavior with a single Tado thermostat + a wireless Tado temperature sensor + dumb radiator thermostats (the wireless Tado temperature sensor is needed because I have a multi-floor home).

  • @Valaki1234

    Some of the cycling can also be due to the SRVs being a poor judge of actual temperature. That's the other issue. I added a wireless temperature sensor into one room with the SRT as it was completely wrong most of the time. That has improved things too.

    I'd leave it for 2 weeks or so to see if it calms down. Mine was certainly a bit odd to start with.

  • gary333
    gary333 ✭✭✭
    What’s also possible as reported on here by others is the SRV’s are limiting the flow through the radiators rather than opening to 100% when calling for heat.

    By not opening fully they restrict the flow, thus increasing resistance. If the pump isn’t modulating (or if like mine it’s on as low as it can go, but still too powerful) it can result with water trying to short circuit round closer radiators, or a situation where the radiator isn’t getting enough flow of water to achieve its design rating and thus the boiler cannot get rid of heat, so shuts down early.
  • I think in my case the latter happens, I asked support to open the valve fully when there is a heat demand but they replied it is not possible.

  • gary333
    gary333 ✭✭✭
    Something I could do with them doing for me too, might quiten the flow on the non TRV rads.