No power to Rc wire detected

[Mattddulk]

So I got the thermostat installed and set up. I did the compatibility test and it all passes. Super easy install. I attach the thermostat to the base and flip the power back on. I keep getting an error that there’s no power in the Rc chord and the AC or fan won’t turn on. I mess around with it, straighten wire etc and still nothing. Eventually I put the old Braeburn thermostat back on and everything works. So I know there isn’t an issue with the power source or wire. Anyone else have this? Would a Nest technician be the best to have come out?

[Rob420]

I'm having almost the same issue.  Came home to blown 3A fuse on the 28VAC (Rc) line and message on Nest saying same as yours.  I replaced the 3A fuse (inside the blower unit), connected the dial to USB charge cable, waited an hour, the dial says to "reattach the screen to the base".  Attaching dial to the base still says no power to Rc line.  Replaced Nest with an old thermostat and the A/C works just fine.  Put the Nest back on and same error.  Voltage between Rc and C is 28vac.  Even moved the 28vac Rc wire to the Rh post, same error msg.  Is it possible the base it toast / needs replacing?

[zoeuvre]

Hi folks, 

Thanks for posting here in the Community forum, and I'm sorry to hear about the situation. Let me take a look at this for you.  

@Mattddulk, please answer the following: 

1. When was the thermostat installed?
2. Who installed the thermostat?
3. Do you still have a photo of your old thermostat wiring configuration? If you do, please send it to us along with the wiring photo of your Nest Learning Thermostat.
4. What are the power readings of your Nest Learning Thermostat under Settings > Technical Info > Power?
   • Battery
   • VOC
   • VIN
   • IIN

@Rob420, please remove the thermostat display from its base, check if any connector pins are bent, and check if the thermostat wires are secured in their terminals and all the buttons are down. Also, for how long did you charge the thermostat display?

I'll look forward to your responses. 

Best,

Zoe

[Rob420]

No bent pins on the display, all buttons are down, charged display for over an hour.  As another test, I relocated a base from a second Nest Learning Therm to the failed location, and the "new" base worked with the the original display.  Put the original base back on and same error Rc error. 

Power menu of original base shows:
- Battery: 3.823V
- Voc/Vin/lin: n/a

Power menu of relocated base shows:  
- Battery: 3.923 V
- Voc: 34.17 V
- Vin: 34.17 V
- lin: 200 mA (c)

For addition info:

- Software version: 6.2-27
- Model: Display-3.4

I think the base on my approx $200 thermostat died. 

[Markjosephp]

Hello folks,

I wanted to stop by and see how I could help.

To isolate: could you please share with us a photo of your thermostat's wiring, @Mattddulk? Also, based on your old thermostat's power readouts, @Rob420, It appears to be an issue with its base. Please fill out this form and let me know once you're done.

Thanks for looking into this, Zoe.

Regards,
Mark

[Markjosephp]

Hello everyone,

@Mattddulk, have you managed to take a photo of your thermostat's wiring? Let us know so we can move forward.

@Rob420, how's it going? Did you already submit the form?

Regards,

Mark

[Rob420]

@Markjosephp, I'm not sure what information to put in the form for "Community Thread" and "How can we help?" sections.

[Jenelyn_O]

Hey Rob420,

Thanks for checking it with us. For Community thread, just copy and paste the link here. You can just give a brief explanation of the issue you encountered under the "How can we help" question. Please let me know once done.

I appreciate the help, Zoe and Mark.

Kind regards,

Jenelyn

[Rob420]

I have filled out the form as requested.

[Jenelyn_O]

Hello there,

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.

Cheers,

Jenelyn