Nest learning Thermostat (Gen 3) not sending a signal for ''O'' terminal

[harpo79]

Furnace is blowing out hot air when in cooling mode. Had HAVAC men here and this is what they said was the problem. Any advice on ways to fix this or is the thermostst junk? TIA

[CoolingWizard]

Did you verify the Nest equipment settings for the Heat Pump? Energize the O/B wire for Cooling? I ask this because I have never seen a Nest Thermostat suddenly stop like this.  

AC Cooling Wizard

[harpo79]

It has been working for several years. Just started doing this last week.

Thanks

[zoeuvre]

Hi harpo79, 

Thanks for posting here in the Community forum, and I'm sorry to hear about the situation. Let me take a look at this for you. 

A few questions: When did cooling last work? Did you check the O/B wire configuration and try changing the O-wire to B-wire configuration or vice versa? Lastly, do you see a power error code on your thermostat?

Also, please help us with the power reading of your Nest Learning Thermostat. 

1. To open the Quick View menu, press the thermostat’s ring.
2. Choose Settings.
3. Turn the ring to highlight Technical Info then press the ring to select it.
4. Select Power.
   • Battery
   • VOC
   • VIN 
   • IIN

I'll look forward to your response. 

I appreciate your help, @CoolingWizard. 

Best,

Zoe

[zoeuvre]

Hi there, 
 

I wanted to check and see if you are still in need of any help. Please let me know, as I would be happy to assist, and answer any questions you may have.
 

Thanks,

Zoe

[zoeuvre]

Hello folks, 

@harpo79, we haven't heard from you in a while, so we'll be locking this thread if there is no update within 24 hours. If you run into any more issues in the future, please feel free to create a new thread.

Regards, 
Zoe