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Nest not turning on Condenser, not cooling

Kelli
Community Member

we have figured out after a few hot days that our house isn’t cooling and the condenser is not turning on when we turn the AC on, no matter the temp or time of day.

Pics of previous set up and nest set up.

help!

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2 Recommended AnswerS

Patrick_Caezza
Diamond Product Expert
Diamond Product Expert

When you replaced the wireless device did you run a new thermostat cable?

Unless you have a unique system it looks like you are missing the cable that goes to the outside unit. It is a two-wire cable that is connected to the Y and C terminals. Without it, the compressor that is located outside can never turn on.

 


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View Recommended Answer in original post

Melba, thank you for checking back with me.  After further research we determined that there was never C connected at the heat pump board.  After making the C connection to the spare wire in the cable, it worked great

View Recommended Answer in original post

13 REPLIES 13

nlambright
Community Member

Thank you for posting this.  I'm setting up Nest thermostat for the 1st time in our house with the same issue. Will post a solution if I can find one

PeteMagoni
Community Member

You probably have a bad capacitor on your air conditioning unit. All air conditioners have a capacitor start if the capacitor is bad the condenser won't turn on. 

Kelli
Community Member

Even if it worked perfectly fine the day before we switched to the nest?

but I’ll still look into checking that.

nlambright
Community Member

From the research on my scenario, I need to get a power connector (my condenser & entire system works fine with the previous thermostat).  If the condenser stops working after no previous problem, it can be low battery in the Nest thermostat, or it could be the capacitor.  If you still have the old thermostat, reconnect it.  If it works, that will provide the answer

Patrick_Caezza
Diamond Product Expert
Diamond Product Expert

Do you have a conventional system or a heat pump?

Post a picture of the terminal block on the control board in the furnace/air handler.

 

 


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Here is the picture;

 

D0032108-60D0-469F-A2F1-6C147D7492B8.jpeg

Patrick_Caezza
Diamond Product Expert
Diamond Product Expert

When you replaced the wireless device did you run a new thermostat cable?

Unless you have a unique system it looks like you are missing the cable that goes to the outside unit. It is a two-wire cable that is connected to the Y and C terminals. Without it, the compressor that is located outside can never turn on.

 


To ensure that I see your reply, please tag me using @Patrick_Caezza

Thank you for your help. I was able to rewire the correct wires into the Y and C ports and now everything works as it should. 

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Patrick_Caezza
Diamond Product Expert
Diamond Product Expert

Perfect


To ensure that I see your reply, please tag me using @Patrick_Caezza

MelbaDT
Community Specialist
Community Specialist

Hey folks, 

 

Thanks for taking care of this, Patrick_Caezza. 

 

Kelli, thanks for keeping us in the loop and we're glad to hear that you've got a working thermostat by following Patrick's suggestions. Hats off to both of you!

 

nlambright, how about your thermostat? Still need help with it?

 

Best, 

Melba

 

Melba, thank you for checking back with me.  After further research we determined that there was never C connected at the heat pump board.  After making the C connection to the spare wire in the cable, it worked great

MelbaDT
Community Specialist
Community Specialist

Hi nlambright, 

 

Awesome — glad to hear that you're sorted it out as well and now, you've got a working thermostat. Feel free to let us know if anything comes up. 

 

Cheers, 

Melba

MelbaDT
Community Specialist
Community Specialist

Hi, 

 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.

 

Best, 
Melba