Nest Thermostat blowing cold air

[sdoyle80]

In the summer, I replaced an old Honeywell thermostat with a Nest learning thermostat on a basic furnace. Everything was working fine in the summer (blowing cold air),but now that winter is approaching the thermostats is still blowing cold air on the heat settings.

Please help!

[SoriaD_]

Hello @sdoyle80 

Thanks for reaching out to our Nest Community. I apologize for all the inconvenience. Don't worry, I'm happy to help you.

To better assist you, I have some questions related to your device and system:

• What model of Nest Thermostat do you have? 
• What is the brand/model of the HVAC/heat pump?
• Could you tell me the wiring configuration on the thermostat base?

Feel free to keep us posting, we're here to find a solution for you.

Best regards.

Douglas.
 

[sdoyle80]

Hi Douglas, I have a Trane XR90 Furnace. 

I have attached photos of my original thermostat wiring, new wiring , and specs of my new thermostat. 

Thanks for your help. 

 

 

 

[SoriaD_]

Hello @sdoyle80 

I really appreciate all the details you provide me. Let's find an answer..

It's certainly not a normal situation, but don't worry; I'll do my best to find an accurate answer to your question.

I've checked your system manuals, and there's a chance that the problem is with the internal wiring of the system.

That being said, let me ask you if it's possible to post a photo of your system's control panel where these wires are connected to your thermostat. This way we'll have a clearer idea of the solution to this situation.

Keep posting; I'll be very happy to help you.

Best regards.

Douglas.

[sdoyle80]

Hi Douglas, I have attached some photos of the inside of my furnace. Are these the photos you need?

 

 

 

[SoriaD_]

Hello @sdoyle80 

Thanks again for all the details you provided me, I really appreciate it.

My team and I have been checking the images with the instruction manual for your Trane XR90 Furnace to which we have seen some inconsistencies in the wiring for the thermostat to perform this function. According to your manual, to perform this action there should normally be a cable connected to the "Y" port coming from the outdoor unit.

That said, for your safety and to be completely sure, we recommend that you contact a specialized technician to determine the solution to this situation and make the necessary changes to your unit so as not to have any problems.

Feel free to keep us posting, we re happy to help you.

Best regards,

Douglas.