Hello Mark,
Please try the following step-by-step procedure including the trick with the 2 cent coin. We have recently learned that around 10% of the valves used in Germany have a slightly too small stroke, the coin compensates for this.

1. Delete Eve Thermo from Eve app
2. Un-mount Eve Thermo and make sure that you can move the valve on heater side (if not use grease and eventually hit the valve's body with a hammer to solve the problem)
3. Put new batteries in Eve Thermo ("Er" means either calibration problem or discharged batteries)
4. Press one of the arrow on screen until "Er" disappears (the screen will then show "no", which means "mounting" and the valve will move to a correct mounting position)
5. Hard reset Eve Thermo until the 66/99 appears on the LED.
6. Re-pair Eve Thermo in Eve app and follow instructions to mount it and calibrate it.
7. Insert a 2 cent coin into the valve holder of Eve Thermo.
8. Follow the assembly and calibration instructions.

If the code ER does not appear on the display of the Eve Thermo during step 4, please skip this step.
Aug 30, 2020