Fan issue fan not running when AC kicks on

[Crashdavis]

We just installed the google nest learning thermostat. Everything seemed to go well with set up. However I noticed that the fan only comes on when I program it to run. The fan does not come on when I hear the AC turn on. Formerly, the fan came on anytime the AC unit kicked on, now,  I can only get it to run by forcing it to come on thru the app. Needless to say, the house isn’t cooling without me manually running the fan. 

I have checked and double check the wiring.. is there something i’m missing?? 

[HVAC · Accepted solution]

that Is odd because you’re able to turn on the fan by itself & it works. Usually when you turn on AC thermostat makes that connection. Check your menu set up on how to set up AC mode & ask it to have the fan come on when AC comes on. Normally you tell nest in heating mode if you want it to turn on the fan in electric or heat pump system or you want equipment to turn on fan in gas heating but shouldn’t be an option for fan in AC mode fan should be able to come on by itself. Double check what you had set up AC mode for possibly take pics of neat wiring plate & air handler circuit board to confirm proper connections. Some equipment does delay turning on the fan for few seconds when AC turns on but shouldn’t take over a minute. Good luck 

[Lokid]

I'm having same problem and my nest has been installed correctly for 2 yrs. Fan shutdown at AC call. 

[Markjosephp]

Hello folks,

I wanted to ensure that everything was covered here.

I appreciate your input, @HVAC.

@Crashdavis and @Lokid, thanks for reaching out with your inquiry. In addition to what was shared above, it's most likely a configuration setup. Please check out your thermostat's settings, as the options may vary from the Nest Thermostat's versions you have. Also, here's an article to learn more about Fan control with a Nest Thermostat.

Let us know if you have more questions.

Regards,
Mark

[Crashdavis]

My problem ended up being a configuration issue a uninstalled. It reset it to factory settings and completed set up with a different configuration for my unit and it worked fine.

[Markjosephp]

Hello Crashdavis,

That's great news! I appreciate your update on what you've done to make it work. It looks like we can consider this one complete, so feel free to create a new post for future inquiries, unless I can help out with anything else.

Regards,
Mark

[Markjosephp]

Hi Lokid,

It has been a few days since your last reply. Let me know if you need anything from me. But you are free to create a new post whenever you need help.

Regards,

Mark