No cool mode

[Nestoronto]

Hello,

New install. Heat works well but there is no cool mode. Not sure about the wiring perhaps 

Current thermostat

 old thermostat

[Patrick_Caezza]

You don't have a cooling mode because you don't have a Yellow (Y) wire. Your original thermostat was wired for heating only.

[Nestoronto]

Hello, thanks for the reply. The a/c worked with the old thermostat though.

[Bzink]

I have the same issue and can’t find information to fix it.

[Nestoronto]

Hey,

So I checked the board on my furnace and it turns out that the black wire is connected to the y on the board. So I connected it to the Y on my best and now the cooling is working. But now there is nothing connected to C on the thermostat so not sure what that would mean for the function of the NEST

[Bzink]

Thank you, I will take a look! 

[Patrick_Caezza]

Having the C wire installed means that the thermostat is powered by the HVAC system all of the time and does need to use the batties except during a power outage.

I always install a C wire when I install any thermostat. It always helps stop any problems down the road.

[Nestoronto]

I agree and that's what I was hoping for when I installed it originally. However the black wire on the furnace board was attached to Y and when I did the same it turned the ac on. But I appreciate your reply and I will have to figure out a way to install the c wire from the furnace to the thermostat.

Just as an aside, what issue should I expect with out the c wire in the mean time

[Ryan_G]

Hi Nestoronto,

Thanks for reaching out here in the community.

Nest thermostats are designed to use very little power, and in many cases they can use your system’s heating and cooling wires to get enough consistent power. But sometimes, you may need to connect a common wire (C wire) or power accessory to prevent some problems like low battery message or Wi-Fi disconnection problem.

Check out this link to know more about it.

Thank you for your help, Patrick_Caezza.

Best regards,

Ryan

[Ryan_G]

Hey Nestoronto,

I just wanted to follow up and see if you're still in need of help. Please let us know as we would be happy to answer any questions you may have. 

Best regards,

Ryan

[Ryan_G]

Hey Nestoronto,

Thanks for being here in the Google Nest Community. 

I'd like to bump in here and make sure that you’ve seen our response.

Please let us know if you have any other questions or concerns as I will be locking this thread in 24 hours.

Have a great day.

Best regards,

Ryan