Neet thermostat does not have cooling mode

[Salim1234]

Hello - I have a nest thermostat, connected to google home but only providing me with heating mode. No cooling mode.

I have C,W, G and R wires connected.

I read some posts and it says I need the Y wire for cooling?

I was reaching out becauae I just moved  in to this house and the seller is saying that they had cooling working with the current wiring configuration. Please help. Thanks!

[Salim1234]

Note my thermostat says equipment N261

[CoolingWizard]

@Salim1234 , can you very carefully pull the Nest display off the back plate, take a picture of the wires that are attached and upload it here. Your seller made a false statement of fact to you. BTW, had you had a licensed Home Inspector this failure would have been found and the seller would have to have had to correct  it before closing. 

I’m going to provide you now a little bit of education on the conventional HVAC control wiring.  If there is no wire on the Y terminal, There is no cooling possible. 

The R terminal is for 24Vac Power IN

The C terminal is for 24Vac Power (the “Common”)

The G Terminal is output to Fan Relay

The W terminal is output to the Heating Relay, this starts the heating cycle

The Y terminal is the output to the Compressor Relay, this starts the cooling cycle. 

There is no thermostat in the world that knows the color of the wire that is attached to a terminal. As a basic standard in the HVAC control wire colors used are red for R, green for G, blue for C, white for W, yellow for Y.  The real key is whatever you attach at one terminal, just attach the same color at the other end same terminal.

I hope this helps you understand.

AC Cooling Wizard

[Salim1234]

Thank you for wanting to help me!

During the home inspection, it was very cold outside and the home inspector noted “not able to test AC due to cold tenperature”.

Within the google home app, in settings, I was able to bring up the cooling icon, by updating the wiring and selected the wire Y.

However, the wire Y is missing from the physical wiring, please see attached picture.

The seller, a honest and nice person, is still me they used to run AC with the current config.

The HVAC is nice and kind of new, it’s hard to think that all the installation was done nicely and properly and would missed to run one wire and still claimed they have AC?

[Salim1234]

 Thank you very much!!

[CoolingWizard]

I feel we should do some due diligence and see if there is an additional wire conductor available.

did you install this nest thermostat yourself or was it already there?

What you need to do is press the tabs and pull all the wires out of the nest back plate.

Once the wires are all free, pull the cables out of the wall until the thermostat cable comes put.  You need to look to see if there is another conductor wire back inside the wall somewhere.

AC Cooling Wizard

[zoeuvre]

Hi Salim1234, 

Thanks for reaching out to us. I hope you've already gotten the answer you're looking for from the troubleshooting steps that CoolingWizard shared. Also, a few questions: Does your previous thermostat control the AC? Do you have an AC unit in your home? Lastly, can you help us with the power reading of your Nest Thermostat 2020 by going to Settings, slide down to Equipment, then tap Power Info. 

I'll look forward to your response. 

I appreciate your help, @CoolingWizard. 

Best,

Zoe

[Salim1234]

Hi Zoe. I just purchased this house and it already had the nest thermostat that is in now.

Power info:

Vin: 27.054V

lin: 35

PS: C-35

Thermostat does show AC but it is not kikcking on.

yes, there is the HVAC unit and a condenser outside.

I will attach pictures.

[Salim1234]

 

[Salim1234]

 

[zoeuvre]

Hi folks,

@Salim1234, thanks for the follow-up information. I see from here that your Nest Thermostat 2020 doesn't have a wire connected to Y, which is responsible for your AC. Can you send us a photo of your HVAC control board where the other end of the thermostat wires are connected? The HVAC control board is where the thermostat wires connect to your heating and cooling system. In most cases the control board can be found at your furnace or air handler. It will help us identify if the system itself really controls AC as well.

Regards,

Zoe

[CoolingWizard]

We need to see the picture of the old thermostat before you removed it and showing us each wire attached.  

AC Cooling Wizard

[Salim1234]

Thanks for your willingness to help me.

Attached all the pictures of wiring I could reach. Please let me know if something else is needed.

[Salim1234]

 

 

 

 

 

[Salim1234]

Coolingwizard - I purchased this house with the new thermostat in it already 

[CoolingWizard]

Congratulations, you have a 2-stage gas furnace and the main thermostat cable is attached to the control board.  Now there should be two thermostat cables one coming from the Thermostat and one going outside to the condenser unit. 

The yellow circle is where the cables attach to the control board. The model Nest thermostat you have there is a not  capable of handling 2-stages of heat.  The bad news is whomever installed that thermostat did not properly connect it to the furnace control board.  You need a thermostat with at least 6 conductors.  R, Y, G, W, W2, C. You Nest Thermostat will use the *OB connector for the W2.  

Take a look at that terminal connection point on the Control Board.   See what terminal letter have wires connected. And, get the model number of the Furnace and outdoor condenser unit.  Thank you.

AC Cooling Wizard

[Jenelyn_O]

Hi folks,

I just want to check if you managed to see the response above. Please let us know if you still have questions or concerns, as we'll be willing to assist you further. 

I appreciate your help, @CoolingWizard and Zoe.

Best,

Jenelyn

[Jenelyn_O]

Hi Salim1234,

Checking if you still need help. Please let me know, as I'll be willing to assist you further. 

Thanks,

Jenelyn

[Jenelyn_O]

Hey Salim1234,

Due to inactivity, we'll go ahead and lock this thread in 24 hours. We'd be glad to help you further so if you still need assistance, feel free to start a new thread.

Regards,

Jenelyn