Correctly wired thermostat doesn’t work properly

[OzzyT]

I have 2 thermostats the same and wired the same way. While downstairs works perfectly, upstairs thermostat is turning the AC unit on and off randomly while it is on. Called AC service and they fins out the thermostat isn’t working as it supposed to. Please advice.

[TiMeToRn]

You have 2 nest thermostats, and one of them works perfectly? So you have 1 known good unit.

Have you tried switching the thermostats around? Leave the wires as they are, just pop the thermostats off, keep track of which one is which, then switch them around. Put the good one upstairs.

If magically the upstairs starts working properly, and the downstairs doesn't, then you probably have a faulty nest thermostat.

If there's no change, then there's probably nothing wrong with the nest unit, and your issue is probably to do with the wiring or AC system.

The systems and wiring are identical? Again you have 2 identical things, and one known good working thing.

So you know the wiring, thermostat, and AC system for the downstairs is all correct and working. The upstairs is the same but not working. So if downstairs is working, and the upstairs is not, then they're not the same.

That means we have a classic game of "spot the difference". Bust out your multimeter and figure it out.

[zoeuvre]

Hi folks,

@OzzyT, thanks for reaching out to us. I hope you've already gotten the answer you are looking for. Also, If the air filter is dirty and needs to be changed, I recommend you replace the air filter. Refer to this article for more details. 

Please let us know if you still have questions or concerns, as we'll be willing to assist you more.

I appreciate your help, @TiMeToRn. 

Best,

Zoe

[OzzyT]

Thank you for your quick response.
Switched the thermostats seems like, problem still exist. Is there anything else I can try or would it be possible to get replacement unit.

[zoeuvre]

Hi OzzyT, 

Don't give up on us yet. We'd like to further check on this. Could you fill out this form and let me know once you're done? 
 

Thanks,

Zoe

[OzzyT]

I submit the form. Please update me when you have received. Thank you.

[OzzyT]

Just tried that out. Seems like I have faulty unit. Would it be possible to check if I can get a replacement with any sort warranty left ? 

[Jenelyn_O]

Hi there,

Thanks for the update! I received your form. I'll hand it over to our team. Please keep an eye on your inbox or messages as they will get in touch with you soon. If you have any questions or concerns, please let me know as I'll be locking this thread after 24 hours.

I appreciate your help, @TiMeToRn and Zoe.

Regards,

Jenelyn