I have seen some posts regarding this but no real solution. I just installed a Nest Learning Thermostat on a brand new HVAC system in my home. I have a forced air gas furnace (propane) and forced air AC. My wife complained of cool air coming out of the registers. I looked outside and the AC compressor is running at the same time as the furnace and I am in "Heat" only mode. I have turned the entire system off and on again, then reset the Nest thermostat to factory settings, set everything up again and it is still doing it. At this point I am going to have to uninstall the thermostat and put an old one back on just so heat will work properly and I don't damage the system with AC and Heat running at the same time. Unless I an find a solution, I have a very expensive paperweight.
Any ideas? Anybody have this and found a solution?
This started happening to me on 12/17/22. I tried turning it off, resetting, disconnecting, reconnecting and doing an offline charge. Nothing works. Both my AC and Heat are on at the same time even though Nest only registers that the heat is running. My house temperature isn’t changing bc the AC is combating the Heat!
I'm sorry for the late response and for the issues you're experiencing with your thermostats. I'd love to know more about this.
Could you share with us a photo of your old thermostat's wiring? This will help us check the configuration. Also, please check your thermostats power readouts in their "Technical Info" settings. I'll look forward to your responses.
Thanks for assisting, Mel.
I gave this information in another thread and filled out the form I was given but have not heard anything further on this issue. (https://www.googlenestcommunity.com/t5/Nest-Thermostats/A-C-Compressor-Attempting-To-Run/m-p/340004)