I often have difficulty with the sync. Wi-Fi drops off one or two thermostats while others work fine. I control 17 T-stats for our buildings and seem to have difficulty often.
Coming from a dual zone unit, I purchased this unit because I was told the Nest wouldnt work. I was told this unit would do everything my previous unit did, plus more. It does not. It does not even work with my phone or have an auto mode.