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nest learning thermostat heat pump

raval75
Community Member

Hello,

I have an all electrical system that has an outdoor unit and an air handler unit.  The old thermostat had an emergency heat function which I believe just turns on heat from the air handler unit and not turn on the outdoor unit so it doesn't pull the air from the outside.

thumbnail_IMG_8386.jpg

Here's the current wiring of the Nest Learning Thermostat.

thumbnail_IMG_8986.jpg

Now, there's no hot air blowing even after 30+ minutes.  By increasing the temperature on the thermostat, it  sometimes trigger the "emergency" AUX heat pump and that's when hot air starts blowing.  But the outdoor unit is still on unlike the previous set up where that the outdoor unit is not running if "emergency heat" is on.

My question is, what's wrong with the wiring to correct is so that...

1) Hot air comes out when not on emergency/aux heat

2) The outside unit turns off when it goes to emergency/aux heat

5 REPLIES 5

CaptKirk
Community Member

The wiring looks right might try switching the white to W1 as that is the heating wire. Emergency heat will pull from the systems heading strip when it's too cold outside for the compressor. Might also be related to s setup with the nest thermostat. I selected one wrong setting and only got hot air. 

raval75
Community Member

Hi CaptKirk,

I switched the white to W1 and that looked like it solved my second issue - now when emergency heat runs,  the unit outside/compressor no longer runs - thank you!

I just find it odd that when nearing the target temperature, Nest will stop the emergency heat and pull air from the outside thereby start blowing cold air negating what it just heated and basically starting the cycle of trying to turn on emergency heat again.

I think it's still a bit cold outside (40F) to test for my other issue of heating when pulling air from the outside even though from what I've read/research it should work fine at least at 35F and above.  The outside unit is a bit old (about 14 years old) so that could be a factor. 

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@CaptKirk, thanks for the help!

 

@raval75, thanks for reaching out. I'm glad to hear that CaptKirk's response helped you with one of the issues. Please try getting the heat from the outside unit once the temperature goes to the recommended operating temperature.

 

Thanks,

Edward

EdwardT
Community Specialist
Community Specialist

Hey raval75, 

 

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

 

Thanks,

Edward

EdwardT
Community Specialist
Community Specialist

Hi raval75, 

 

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

 

Thanks,

Edward