Heat pump turning off randomly

[Jaredskoipond]

Hey all,

pretty frustrated. Bought a house with a nest learning thermostat. Had heating issues with a compressor and got an entirely new heat pump. Had issues with the nest where below freezing it would stop working. Figured it was due to accidentally being reset as dual fuel to kick on aux for gas when I just have electric. 

but still I have random days/ episodes when my heat pump just turns off. My nest shows it’s on and trying to pull heat and the air handler is on. But the vents blow cold air. 

I try turning nest off then back on. I check the heat pump and it doesn’t turn on and my vents are just blowing cold air. Usually happens at night time once temperatures drop. But it withstood some 10*F with windchill nights then wouldn’t work tonight when it’s 24*F. 

then randomly at some point in time hours later I’ll turn on my heat and the heat pump kicks back on. I’ve called my HVAC installer who thinks it’s a NEST problem. Not sure if it’s BS. 

here’s my set up. 

[Jaredskoipond]

 

 

my connections for reference. 

[Jaredskoipond]

I should add our house has two HVAC systems. Our heat pump for upstairs works perfectly fine. Hasn’t needed replacement and kicks on even in freezing temps. Also is a nest learning thermostat

[MelbaDT]

Hey Jaredskoipond, 

Thanks for reaching out and for providing a detailed description of your concern including the photos. 

In order to easily isolate if the issue is on the Nest Learning Thermostat or your HVAC system, could you try swapping your upstairs thermostat including the base to this one in question?

Let me know how it goes. 

Best, 

Melba

[Jaredskoipond]

Thanks! I did try and still having issues. I believe you are correct. It isn’t an issue with the NEST thermostat but rather something with wiring. Thank you!