I’m having problem getting my Nest Thermostat Gen3 working properly. After wiring everything, the thermostat functions properly with the exception of 1 problem.
After the house reaches the desired temperature from the heating unit (66F), every 30seconds or so I hear the HVAC unit turn on for maybe 5 seconds and then turn itself off. What am I doing wrong? If i install the old thermostat back, everything works back to normal again. No on/off problem. The old thermostat unit doesn't have the Blue cable connected.
I have tried
My wiring is as follow. Line colors are the actual color of the wire. I am running gas to heat (Forced Air i believe)
The C Wire wasnt used in the old thermostat. I first tried without the c wire with nest, but then it kept turning the hvac on and off every 30 seconds. Read online and people say it's because it needs the c wire. So i use the c wire, and it was detected by nest just fine, but the problem still persists.
Thanks for reaching out and we're sorry to hear about what's happening.
Other than the C (common wire), we should also check the equipment selection and make sure that we've chosen the right heat type and source. Go to settings > equipment > select the right heat type and source then test your equipment.
Thanks for your help, Patrick_Caezza.
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Your wiring is correct for a conventional system which it appears that you have.
Try doing a factory reset to default and setting it up again.