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Google nest thermostat running through AAA batteries every 2 months

Nestuser1111
Community Member

Hello everyone! I have a dual zone HVAC and seem to have a small issue. Both zones have a nest thermostat hooked up (one runs most floors while the other runs only upstairs bedrooms and living room in townhome). Both show approx the same metrics; Vin: 36, Lin: 385, PS: C-385 while the AAA read 3.2 volts new. The upstairs unit goes through the AAA batteries in about 2 months while the downstairs has yet to be changed (approx 11 months and going). Upstairs is used a little more with HVAC system. Any thoughts on why the upstairs nest is using more batteries? Thanks!

15 REPLIES 15

Patrick_Caezza
Platinum Product Expert
Platinum Product Expert

Do you have a C wire installed on either?

Post a picture of the zone controller's wiring.

 


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

FA1824BB-D93F-460C-B0A2-DEC125FE639E.jpeg

Not quite sure how to post a picture on this forum but I have a picture

Here is another pic

E8F4F3F5-DD53-4DC9-B654-4650ED536BFF.jpeg

Looking at this picture and on the right are two two connection points for the thermostats, the second terminal from the bottom of each terminal block is the C wire connection point. It looks like the black wire going to your thermostats is a C wire. Where does the black wire connect to on the Nest thermostats?


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Goes here:

DE11E66A-7C99-4870-8690-0CB92543D325.jpeg

Do you have a multimeter or such that you can use to measure the voltage between the red and black wires?

Are both the upstairs and house thermostat the same? If there are, have you tried swapping the displays on them and see if the battery issue follows or stays?


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Haven’t tried swapping the displays yet that is a good idea

Ryan_G
Community Specialist
Community Specialist

Hi Nestuser1111,

 

Thanks for reaching out here in the community.

 

I'd like to jump in here and check if you've already tried swapping the Nest thermostat display. Let us know how it goes by replying to this thread.

 

Thanks for your help, Patrick_Caezza.

 

Best regards,

Ryan

Ryan_G
Community Specialist
Community Specialist

Hey Nestuser1111,

 

I just wanted to follow up and see if you're still in need of help. Please let us know as we would be happy to answer any questions you may have. 

 

Best regards,

Ryan


 

Yes I first tried re seating the C wires to see if that was the problem and am currently testing that method. I will swap if low battery happens 

Ryan_G
Community Specialist
Community Specialist

Hey Nestuser1111,

 

Thanks for the update. Let us know how it goes by replying to this thread.

 

Best regards,

Ryan

Ryan_G
Community Specialist
Community Specialist

Hey Nestuser1111,

 

I just wanted to follow up and see if you're still in need of help. Please let us know as we would be happy to answer any questions you may have. 

 

Best regards,

Ryan


 

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

Nestuser1111
Community Member

Thinking about it maybe a good start would be just a reseating of the zone two black wire to make sure has a good connection if the zone one batteries are lasting a long time maybe it’s just the connection with the C wire and zone two?