I just replaced my old Nest Gen 3 thermostat with a new Gen 4 thermostat. I have a 4 wire HVC. I'm seeing the same issue. Heat works, fan works, but the AC unit does not turn on. Seeing the same message on the app. Thoughts?
I had an HVAC company come out. The “contactor” had gone out on my AC unit. So it was shorting out. That’s why my AC would try to turn on and would immediately turn off.
I am having the same issue. I installed the thermostat a year ago and it was working fine all summer. When I switched to heat in the fall it would not control the furnace and started blowing fuses. Turns out it was the google module that provides the C wire that was causing the fuse issue. The tech removed the module and installed a new six wire thermostat cable so all wires were present. He programmed the thermostat and the furnace worked well all winter. Now when I turn on the AC, the unit starts up just fine and runs for about 30 seconds and then shuts down with the system will start soon message. The tech had a similar issue with the furnace but he was able to program the thermostat to make the heat work okay. I only see heat in the device settings on the app. Do I need to reprogram the thermostat to include AC? I have two separate systems for heat and AC.
All I know is that for me, the AC unit would short out everytime it tried to turn on because there was a bad contactor in the AC unit. So it was a problem with the AC unit, not the thermostat.
