Yesterday I installed a tado° smart thermostat in our apartment. The tado replaced a Honeywell CM901 thermostat and is connected to a Viessman Vitodens 100-W WB1A boiler. This post gives an overview of the installation process and my notes on troubleshooting the tado.

The tado (December 2013) is actually three devices:

  • tado gateway/bridge – Connects to an internet router via an ethernet cable.  Communicates wirelessly (6LoWPAN, 868 MHz) with the tado box. Needs USB power.
  • tado box – Connects to the boiler and controls when the boiler starts or stops heating. Powered by USB power (or by the boiler in some cases).
  • tado temperature sensor – Measures the temperature and communicates wirelessly (6LoWPAN, 868 MHz) with the tado box. Has an internal battery that is normally charged via solar cells on the device. Can also be charged via USB power.

A USB power adapter and a very short ethernet cable are included. It should be pointed out that if you can’t get USB power from your router and you also can’t get power from your boiler, then you will need a second USB power adapter.


The installation process was fairly straight forward, though not trivial. If you want you can pay tado° to have one of their engineers do the installation. The tado doesn’t come with a printed installation manual. Instead you log on to the tado° web site and follow an installation wizard. I suggest doing this on a tablet or laptop since you will probably want to have the instructions at hand by the boiler during the installation.

Following the steps in the wizard was okay. Although there is this video on YouTube, what I missed was an overview of the entire installation process. Also, once the tado is installed and working, there doesn’t seem to be a way to access the wizard again in case you want to look something up.

The installation starts with connecting the tado gateway to the internet. This was trivial. The wizard immediately detected that the tado gateway was online.

Next was installing the tado box by connecting it to the boiler. This was by far the most nerve-racking part of the installation. In summary, you have to open your boiler, disconnect the old thermostat and connect the tado box instead. I recommend carefully studying the schematics of your old thermostat and comparing them to those of the tado box. It worked out in the end. The gateway and box found each other and the “link” LED on the gateway lit up. The wizard detected that the box was connected.

The last step was installing the tado temperature sensor. I removed the protective foil from the solar cells as instructed, but the wizard did not detect the temperature sensor. I tried reseting the sensor with a paper clip, but that did not help either. I then connected the temperature sensor to USB power to charge it (tado° recommends 24 hours). I continued trying to get it to work while it was charging. I reset it a couple of times and eventually the temperature sensor’s LED started blinking. Still no connection though according to the wizard. Maybe the temperature sensor did not have enough charge yet? After several reset attempts and some waiting the wizard detected that the temperature sensor was online. I could complete the wizard and finish the configuration. Everything was working.

My tado soon started having problems though. The tado web site and the mobile app would either not show a temperature reading or would complain that the tado box had no internet connection.

Dropped connections

Dropped connections

In our apartment the internet router (with wifi) is in a cabinet together with a cable modem and the fuse cabinet. After lots of testing I eventually replaced the provided ethernet cable for the tado gateway with a longer one and moved the tado gateway as far away as possible from the other equipment in the cabinet. Since then I haven’t had any problems. I think interference from the other equipment was causing the connection gateway-to-box to drop. I think the reason the connection box-to-temperature sensor was dropping was because the temperature sensor’s battery initially didn’t have enough charge.


First, I should point out that the tado° support team was quick to answer my questions on Twitter. I should have tried contacting them earlier to save myself some grief, but I simply assumed there wouldn’t be any customer support over the weekend. It’s nice to be pleasantly surprised!

When the tado has connection problems the Android app and web app show instructions on how to solve the problem. There is also a FAQ in the web app under the Support menu item with some useful tips. Sometimes though, I found that the instructions didn’t always fix the problem. Below are my notes on the different failure modes of the tado that I noticed and what actions seemed to help.

Disclaimer: My notes may not be correct. Use them at your own risk.

  1. Blinking LED on tado box and blinking “link” LED on tado gateway and error message in app about no connection to the internet
    1. Reset tado box using paper clip.
    2. Optionally (?) reset tado gateway using paper clip.
  2. Blinking “link” LED on tado gateway and error message in app about no connection to the internet
    1. Unplug power from tado box.
    2. Thermostat switch in tado box clicks (not always?).
    3. Plug power in again.
    4. “link” LED on tado gateway stops blinking.
    5. Web app shows yellow status for inside temperature but no temperature is displayed. I assume this means the tado gateway has a connection with the tado box, but the tado box has not received a temperature reading from the tado temperature sensor yet.
      Inside temperature not detected
    6. LED on tado box continues blinking. (What does the blinking LED mean?)
    7. Reset tado temperature sensor using paper clip.
    8. LED on tado box switches off.
    9. Web app shows inside temperature.
    10. I think it would be more convenient if the LED is on when a connection with the temperature sensor is established.
  3. tado temperature sensor has no connection
    1. Reset the temperature sensor using paper clip.
    2. The temperature sensor LED blinks 28 times. (Why 28 times?)
    3. The temperature sensor LED switches off.
    4. Web app shows inside temperature.
    5. I think it would be more convenient if the LED is on when a connection with the box is established. Or would the LED use too much power if constantly on?


Once my supposed interference problems were solved earlier today, the tado has been working perfectly. It will be very interesting to see how well the geofencing works tomorrow when we leave the apartment for work.

tado° dashboard

tado° dashboard

Update: tado° support has provided me with info about the LEDs:

  • tado box LED
    • orange – home button was pressed
    • green blinking – no connection with the tado gateway
    • off – everything is working
  • tado temperature sensor LED
    • green blinking – no connection to the box
    • off – everything is working

I think the problem with using the LED in off state to indicate that everything is working is that it could also mean that the device has no power (or be defective).