If the AC unit does not start up when an Airzone system zone is switched on, run the following checks:

Check that the Airzone system is set to an operating mode other than Stop and that the set-point temperatures generate demand. If you have any doubts about the behavior of the operating modes see Airzone operating modes.

If the operating mode is properly selected, check that the Airzone system generates demand correctly. To do so, check that the relevant damper opens when demand is generated in one of the zones and LED D6 of the main control board associated to the AC unit's On/Off relay is lit up (green).

If the On/Off relay is on, the system's demands are operating properly and the problem must be in the system's communications with the AC unit. To continue with the diagnosis of the problem, follow the steps set out at the following link: The dampers open and close, but the AC unit does not start up.