Experienced HVAC and electrical technicans stumped by Nest Thermostat

[EricLevinson]

Last week, I woke up to my AC going on and off and on and off over and over again.  It must have cycled 100 or more times by the time I woke up.  Note AC works fine, its well maintained.  I subscribe to OhmConnect and they are unable to tell me anything.  They keep referring me back to Google.

The thermostat would do the following:

It would go to Cooling mode for 45 seconds.
Then it quickly flashes ECO on the screen, then, shows Cool set to:  Starts in 2:30 and it is counting down.

Once it counts down, it turns the AC on again.   Every 3 minutes my AC was being "Thrashed" by this thermostat until I shut the whole thing down.  Needless to say the house was not cooling off.

No error codes, or anything on the screen or app.

After reviewing documentation online for this issue and how to solve when NEST is not detecting properly (does not exist anywhere online) I decided to do a factory reset of my thermostat.

Low and behold it works great now, except for it isn't detecting my green wire now, and there are no Fan options.  For example, I cannot set a fan schedule nor can I turn on the fan.

The green wire is working and active.  Not sure why all of a sudden the thermostat doesn't detect the wire.

Here's my questions:

1) The green wire was not detected, even though there's power and it works.  Do I need to do another factory reset to get it to detect the wires again?  Maybe the thermostat or base defective?  Documentation says it checks both electrical and mechanical connections.  How do I get a replacement?  This was all free from OhmConnect.
2) Why was my thermostat thrashing the AC?  Had I not awoken I might have been looking at $20K to replace the AC.  Since I did a factory reset of the thermostat, its not in the app for me to see the logs.  Is this what happens in the code of the thermostat if it thinks the fan is not working?  How can I get my logs for a thermostat I had to factory reset?

[Patrick_Caezza]

@EricLevinson 

How do you have it wired? Can you post a picture of the wiring?

Is there a C wire installed?

[EricLevinson]

Yea there's a C wire.  The technician confirmed there's no power stealing going on.

[EricLevinson]

Here it is - same wiring since 2018.

@Patrick_Caezza

[EricLevinson]

I just got off the phone with a technician at Nest over the support chat.  He had me try a myriad of combinations of wiring in the thermostat.  He kept getting some backplate error codes.  He is sending out an advance replacement and will swap this out - free of charge.  Will follow up with thread once I receive new backplate and thermostat and install them.

The technician still had not answered why the standard failover for this type of malfunction is trashing someone's AC.  It shouldn't be that way.  

@Patrick_Caezza

[Patrick_Caezza]

@EricLevinson 

While you are waiting for the replacement can you post a picture of the control board terminal block that's in the furnace/air handler?

[EricLevinson]

I posted it in an earlier post.

[EricLevinson]

Received a delivery notification - however thermostat was not received, or it was delivered to a different house.  There's a "signed by" name there I don't recognize.  I notified Nest and Google store customer support.  

[Guarcax]

Hi @EricLevinson,

Thanks for reaching out to the Community. I understand that you were supposed to receive a replacement but it was not delivered to you.

To assist you better, we'll need some additional information. I'm sending you this form where you can provide all the necessary details and also please fill out all the information required.

Once you've completed the form, please let me know. This will allow us to investigate the issue further and find a solution.

Regards,

Daniel.

[EricLevinson]

Thanks.  I notified Nest support and they sent me another thermostat.  It didn't work correctly.  After getting another thermostat I gave up.  

[Guarcax]

Hi there!

Thanks for your reply.
I apologize for all the inconveniences that our Nest thermostat caused to you. I understand that you already received assistance and received a replacement but still having the same behavior and I’m sorry that you gave up with this. Here I send you the feedback form if you want to put your suggestions about the Nest Thermsotat.

If you still want assistance from me, you can reply and I’ll be more than happy to help you.

Regards,
Daniel.

[EricLevinson]

Hi Guarcax.  Unfortunately only a working thermostat will fix this issue.  Feedback won't help.  Since opening this thread I have had several conversations with Google support and now they refuse to send me a replacement without images of the two thermostats I already sent back. I don't have them or the images any more, and its their fault - they required me to send them back to get replacement shipments. BTW I already send all the serial numbers in previous communications but the rep says they are all encrypted and nobody can see the history.  What a JOKE!  
I'm filing a dispute for the original purchase price and requesting punitive damages from Google.  All they had to do is send me a working replacement thermostat and backplate which they were never able to do.  Instead its been over 40 hours on a chat with them over the period of 8 weeks. 

I'll NEVER buy another product that's attached to the Google name again.