Fan keeps running even Nest is off mode

[robhuang]

fan keeps running even Nest is set to OFF mode.  The only way I can stop fan is remove Nest display from the base.  Everything worked just fine until a few week ago. 

Does anyone has the same issue?

[robhuang]

from Nest own document: https://support.google.com/googlenest/answer/9296419?hl=en#:~:text=Press%20your%20thermostat%20ring%....

If there is a wire in your Nest thermostat’s G connector 

• ...
• However, you can only run the fan when your thermostat is set to a temperature mode (like Cool mode, for example). You cannot run the fan if your thermostat is set to Off. 
• ....

This indicates Nest has a defect which keeps running the fan even it is off. 

[Jaywob]

Did you ever resolve this?  After years of working just fine, my fan started last night even though my Nest thermostat is in Off mode.  Do I just need to find a repair person?

[Jenelyn_O]

Hi Jaywob,

Thanks for reaching out. A few questions: what type of Nest Thermostat do you have? You can visit this link to check what type of thermostat you have. Do you see any messages or code on your thermostat or in the app? Please try to remove the display of your thermostat then check if your fan is still running after 5 minutes of the display being removed from its base. 

Best,

Jenelyn

[Jaywob]

No messages.  I have a Nest Learning 3rd generation (I think).  I took the display off, and it's running still 30 minutes later.  

[Jenelyn_O]

Hey Jaywob,

If your Nest Thermostat is removed from the base, nothing should be running. The thermostat shouldn’t be calling for anything, no matter what the last setting was. 

You can follow the guide here: 

1. Shut down the HVAC system at the breaker box. Ensure as closely as possible that all power to the system is off before proceeding.
2. Remove the G wire
   Important: Any removed wire should not touch any other wire, especially not a power wire.Please leave the wire sticking straight out and separated from any other wires before restoring power.
3. Leave the thermostat display off the base.
4. Turn the power back on.
5. Wait for a maximum of five minutes to see if the suspected component still turns on and stays on with the display removed. 

If your system is still activating with the display and fan wire removed, you're having a separate HVAC issue. 

Thanks,

Jenelyn

[Jenelyn_O]

Hi there,

I'm checking back in. Were you able to try the steps I provided above? Please keep me posted.

Regards,

Jenelyn

[Markjosephp]

Hello folks,

Thanks for looking into this, Jenelyn.

@Jaywob, It has been a few days since your last reply, and we're going to lock the thread within 24 hours. If you have any questions, please feel free to create a new post.

Thanks,

Mark