The Remeha Tzerra Ace does not always immediately see that it is connected to a thermostat other than the eTwist. 

Follow these steps to detect a new OpenTherm thermostat such as the Adam and Anna:

  1. Disconnect the boiler from the power supply (unplug from the mains).
  2. Remove the old thermostat.
  3. Connect Adam or Anna to the boiler.
    1. With Adam and Anna: Connect Anna Smile-T to Adam.
    2. Connect Anna to Smile-T.
  4. Connect Adam and/or Anna Smile-T to the internet and power.
  5. Plug the boiler into the mains socket.
  6. Wait until the boiler display has passed the start procedure (until "LOAD" has passed).
  7. Go to the installer menu:
    1. Press (+) and (enter symbol) button simultaneously.
    2. Select with (-)/(+) buttons installer icon (figure with wrench).
    3. Press (enter symbol).
    4. Enter the code "0012" with (-)/(+).
    5. Press (enter symbol)
  8. Run Auto-Detect (AD):
    1. Press (+) until "AD" appears on the screen.
    2. Press (enter symbol).
  9. The screen should now briefly display "INIT". Then the boiler performs auto-detection between R-Bus, OpenTherm or On-Off.


After doing this, Adam/Anna can be used to control the boiler.