tado thermostat: 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).
Applies to: tado° Smart Radiator Thermostat (on the Basic: warning and spanner symbols with six dashes). What you see: a code and a symbol.
What tado says to do
- Use a spanner or similar tool to move the valve pin in and out to free it, or refit the old valve head and open and close it several times; then restart and remount the thermostat.
- If that does not work, the batteries may be low: replace them, then restart and remount.
- If calibration still fails after several attempts, contact tado° by chat with a clear picture of the valve body.
Source
tado’s own help page, read on the date shown.
- tado° Help Center: My Smart Radiator Thermostat displays an E1, E2 or E4 error. How can I fix this? — tado° Smart Radiator Thermostat, including the Basic. support.tado.com Checked 2026-09-29.
A similar symbol on other thermostats
The same symbol on another maker’s thermostat can mean something else.