Nest Learning Thermostat no longer cools with heath pump (no voltage to O/B)

[MavisDavis]

Tried switching the heat pump to cool for the first time this season to find that the Nest thermostat activates Y1, G, but not O which is required to activate cooling mode on the heat pump. Nothing has been changed since last summer when the AC worked. 

I tried resetting the thermostat and doing the setup again, and in test mode it(and normal cooling mode) it is only giving power to G and Y1 and not O/B.

[DMaize]

• I figured I would send you this link as my cooling would turn hot air on instead of cooling my house. I changed my wiring to this and now my thermostat cools my house!!
• https://www.googlenestcommunity.com/t5/Nest-Thermostats/Nest-Learning-Thermostat-wiring/m-p/245941
  
  *** I hope this helps you as much as it helped me!! ***

- Dan

[MavisDavis]

Hi Demaize, thanks for the reply. That's how I currently have my thermostat wired. Again, nothing has changed for the past 1.5 years when heat and cooling worked appropriately. 

[zoeuvre]

Hi there, 

@MavisDavis, thanks for posting here in Community and I'm sorry to hear about the situation. Can you help me with your Nest Learning Thermostat's power reading?  

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
   • VOC
   • VIN
   • IIN

I'll look forward to your response.

I appreciate the help, @DMaize. 

Thanks, 

Zoe

[Jenelyn_O]

Hi there,

Chiming in — could you please provide your Nest Thermostat power readout? It will help us to move forward. Also, do you see any messages or code on your thermostat screen? 

I appreciate your help, @DMaize and Zoe.

Best,
Jenelyn

[Jenelyn_O]

Hello there,

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 need assistance or want to discuss topics, feel free to start a new thread.

Regards,
Jenelyn