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installed and it only blows hot air instead of cool air

Community Member

So my power company, APS sent me 2 new google nest thermastats.  when i went to install it i followed the directions and used my 4 wires correctly.  But the system, while on cool only blows hot.  I put the old thermastat  on and it functions correctly.  I dont know what i am doing wrong.  I have only 4 wires.  I wonder if that jumper on the red wire has anything to do with it.  but i dont know wear to put it on the new google nest one as there is only 1 red wire input on it.  please help

@Patrick_Caezza i think i am tagging you  lol



Community Member

I'm having same issue, but we have 6 wires.  We had to reconnect old one until we figure it out. It was getting too hot in our house to figure out the issue.

Community Specialist
Community Specialist

Hello everyone,

Thank you for taking the time to let us know about your inquiry. I'd be happy to take a look at this for you.

@Paradox1977, a wiring setup might be causing this. To isolate, do you have a heat pump system? If so, try moving the white wire to the O/B terminal in the Nest Thermostat and restarting it to reconfigure. Then, activate your system and check if it works. Also, it would be better if you could share with us a photo of your system control panel showing how the wires from your thermostat are connected. I'll look forward to your response.

@Amy9397 , how's it going with the installation? Have you sorted it out? Let me know more so we can move forward.


yes, it is a heat pump system. I also tried switching the wires like you suggested, and I even tried switching the yellow and white wires also still blows hot I tried going into the Google Home app and looking where I could tell it that what kind of system I have, but all it does is show forced  it doesn’t show heat pump    I hope it is compatible


Hi Paradox1977,

I appreciate your quick response. Try updating the wiring configuration in the Google Home app's Thermostat settings. Your thermostat was initially processed with its original wiring setup; a reset to factory default is optional if the wiring changes won't apply in the app.

Please visit the Nest Thermostat Settings menu for your guide and keep me posted on how it goes.


Hey there,


Checking back in — how's it going? Have you managed to reconfigure your Nest Thermostat via the Google Home app or by resetting it to default? Let us know if you need more help.



Nope. Unfortunately the 2023 model is not compatible with heat pump systems from 1999. 

Community Specialist
Community Specialist

Hi folks,


Got it. We'd like to take a closer look at it. Could you please provide the make and model of your heat pump system? It will help us to ensure the compatibility of your system to the Nest Thermostats. 


I appreiate the help, Mark.