Nest 3 Thermostat turns the fan on for a couple of minutes every hour

[RogerQ]

After replacing an original Nest thermostat with a new  one the fan starts up for a couple of minutes every hour, it doesn't start the compressor when it's on cool and the temperature is set so that the A/C shouldn't be on.  Does it whatever the mode is set to, A/C and heat are working properly when the temperature is set to activate them.

[code_]

Is the heating set to auto at all? Often sometimes if the room is too hot and is on auto, nest will tell the AC to turn on until the room is at the desired temperature you set. 

[RogerQ]

No, and the AC doesn't actually come on (no compressor starts) just the fan for about 2 minutes then it turns off.....

[Patrick_Caezza]

@RogerQ 

Was your original Nest thermostat a Google Nest thermostat (mirrored display)?

How is the new thermostat wired?

Does it have a C wire installed?