I have a nest and whenever I switch from Eco to Heat settings, my AC turns on as well as the furnace. The air coming out of the vents isn’t warm despite the furnace running. Why is the AC turning on? This never happened with my other thermostats. null

Question

ShawnH · Accepted Answer

Dawn,

Sounds like something isn't wired right. I would reach out to Nest and they can assist you. Their support in troubleshooting a software issue with my original thermostat took a bit but they knew what they were doing.

MissPinky · Answer

Have you made sure you have the thermostat connected properly? It sounds to me like you may have the wires set up wrong.

jackyl · Answer

Definitely sounds like it has been installed incorrectly. Check the wiring again

Kking8201 · Answer

If you have a large AC unit it could just be the fan kicking on to start the air circulation in your home. Mine would do the same thing. If you’re switching from Eco to Heat I assume it’s because of winter time and you normally wouldn’t be turning on the AC - in the winter I typically kick the breaker off on the condenser outside (could be a switch by the big unit outside or might be a fuse you pull out and can usually flip around and put back in with the connections not touching) so even if I turn on my AC (on purpose or accidentally) it won’t turn on.

Answered by Kking8201 7 years ago

Verified Purchase

Nipidoc · Answer

Almost certainly something is mis wired. I had a similar issue with a unit that does two stage heating. Probably a good idea to call in a pro.

“I have a nest and whenever I switch from Eco to Heat settings, my AC turns on as well as the furnace. The air coming out of the vents isn’t warm despite the furnace running. Why is the AC turning on? This never happened with my other thermostats.”

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