tado° smart thermostat: what its lights, codes and symbols mean

tado° thermostats and sensors show small symbols on their LED matrix: a battery, a sync or update sign, a pairing chain. The Wireless Receiver by the boiler has its own lights. A code starting with E means something failed: E0 is pairing, E10 is wiring, and on the Smart Radiator Thermostat E1, E2 and E4 are calibration on the valve.

tado° documents its V3+ and earlier devices here: the Smart Thermostat and Wireless Temperature Sensor (on the wall), the Wireless Receiver (by the boiler) and the Smart Radiator Thermostat (on a radiator valve). tado° describes the receiver lights by position, not colour.

1. Low battery symbol

   The batteries are running low and need to be replaced.

   tado° Smart Thermostat and Wireless Temperature Sensor. tado gives no step for this.

2. Depleted battery symbol

   The batteries are depleted and need to be replaced. Changes on the device itself are blocked until they are.

   tado° Smart Thermostat and Wireless Temperature Sensor. tado gives no step for this.

3. Firmware update symbol

   The device is updating to a new firmware version.

   tado° Smart Thermostat and Wireless Temperature Sensor. tado gives no step for this.

4. Synchronizing symbol

   Changes made to tado° have not yet been synced to the device.

   tado° Smart Thermostat and Wireless Temperature Sensor. tado gives no step for this.

5. Legionnaires’ disease protection symbol

   The boiler is firing to disinfect the hot water (Legionnaires’ disease protection).

   tado° Smart Thermostat controlling hot water. tado gives no step for this.

6. E0: pairing failed

   Pairing failed during installation.

   tado° Smart Thermostat and Wireless Temperature Sensor. 3 steps from tado on its page.

7. E10: wiring does not match the setup

   The wiring on tado° does not match the way it is set up to control your heating. While the error shows, tado° cannot control your heating.

   tado° Smart Thermostat and Wireless Temperature Sensor. 3 steps from tado on its page. About wiring or power: only tado’s own instruction is repeated.

8. Wireless Receiver: all lights off

   The Wireless Receiver is not supplied with power.

   tado° Wireless Receiver (UK and EU). tado gives no step for this. About wiring or power: only tado’s own instruction is repeated.

9. Wireless Receiver: connection or pairing light blinking

   The Wireless Receiver is in pairing mode.

   tado° Wireless Receiver (UK and EU). tado gives no step for this.

10. Wireless Receiver: error triangle light on

    You may be having connectivity issues.

    tado° Wireless Receiver (UK and EU). tado gives no step for this.

11. Wireless Receiver: heat light on or fading

    tado° is requesting heat (or, on the UK receiver, hot water). The light is solid on relay systems and fades slowly in and out on digital and analog systems. When it is off, tado° is not requesting heat.

    tado° Wireless Receiver (UK and EU). tado gives no step for this.

12. Radiator thermostat E1: valve closed position not found

    Calibration failed: the closed position of the valve was not detected.

    tado° Smart Radiator Thermostat (on the Basic: warning and spanner symbols with two dashes). 2 steps from tado on its page.

13. Radiator thermostat E2: no contact with the valve pin

    Calibration failed: no contact was detected between the motor and the valve pin.

    tado° Smart Radiator Thermostat (on the Basic: warning and spanner symbols with four dashes). 2 steps from tado on its page.

14. Radiator thermostat E4: valve travel too short

    Calibration failed: the distance between the valve’s open and closed positions is too short, which can mean the valve is blocked by calcification (limescale).

    tado° Smart Radiator Thermostat (on the Basic: warning and spanner symbols with six dashes). 3 steps from tado on its page.

Find a light, symbol or code on any maker’s thermostat →