Nest Thermostat Cool+Fan Configuration

[aap]

Does the Nest thermostat tie the Cool (Y) and Fan (G) wires together when a call for cooling is invoked ? Some older thermostats used to do this. I need to insure that this is NOT the case as the current system (York) has automatic fan controls and speed settings for heat and cool.

[MelbaDT]

Hey aap, 

Thanks for reaching out and sorry for the delay. 

This is dependent on the system that you have. If you have a forced-air system, it runs the fan whenever it's heating or cooling. If your forced air system has a separate fan wire in your Nest thermostat’s G connector, you can run the system fan when it’s not heating or cooling. If not, your fan will only run automatically when your system is heating or cooling. 

Please check this out to know more about fan control with your Nest thermostat: https://bit.ly/2KDDJJw

Best, 

Melba

[aap]

Thanks, MelbaDT.

Good to know how the Nest's handle this.

The newer vintage zone panels (eg: EWC NCM300) handle this and prevent G calls from overriding the built-in speed taps on the furnace until heat/cool calls are satisfied.

Energy/heat recovery ventilators are usually wired on the furnace side controls and break the G wire from the thermostats or zone control boards so they can operate the fan independently as needed without inadvertently invoking Y call for cooling.

[Ryan_G]

Hey aap.

Thanks for being here in the Google Nest Community.

I'd like to jump in here and check on how your Nest Thermostat is doing. You could reply to this thread if you have further questions.

Thanks for the help, Melba.

Regards,

Ryan

[Jake]

Hey aap.

I wanted to check in and see if you managed to see Ryan's post. Please let me know if you have any questions from here. I would be happy to assist, and ensure you are good to go.

Best regards,
Jake

[Jake]

Hey aap.

I want to ensure you are good to go, and everything is working properly. Please let me know if you are still having trouble, as I will be locking the thread in 24 hours due to inactivity.

Best regards,
Jake

[aap · Accepted solution]

All -

The Nest's (3) are working fine with the EWC NCM300 zone panel. Thanks for your assistance.

[Ryan_G]

Hey aap,

Thanks for the reply and it's great to hear that your Nest Thermostat is now up and running with your EWC NCM300. 

We're going to lock this thread as this seems to be resolved and you can always create a new one if you have any other questions.

Best regards,

Ryan