Zone 0 appears on the thermostat when I connect it

If Zone 0 is displayed when your thermostat is connected and it is not possible to move forward from this screen, first check the thermostat's connection. Ensure that the wires are making good contact and are not loose. To do so, tug on them gently and ensure they are not released.

If the thermostat's connection is satisfactory, check that the bus's connection to the main control board is also correct. Check the polarity and that the wires are making good contact with the terminal connection.

If the connections are correct, proceed according to The wired thermostat displays Error 1 - Communications failure between thermostat and main control board , since the error is identical: there are no communications between the thermostat and the system's main control board.