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Nest thermostat with e294 error, R wire not detected

BruceB
Community Member

I installed a Nest thermostat and it gives error e294, need R wire. However, the R wire IS connected. As per troubleshooting instructions I have uninstalled the device from my Google Home app and reset the thermostat to factory settings three times, and it still gives the error. I have also removed and reconnected the R wire from the Nest base plate two times. It still gives the same error. The furnace worked fine with the old Honeywell thermostat, and still does when I reconnected it again. The furnace has a White-Rogers 50A55-843 fan control board. What do I have to do to get the Nest thermostat to work?

1 Recommended Answer

BruceB
Community Member

For what its worth to everyone else, I spent 45 minutes on the phone to Google Next support, and 95%  of what the Customer Service Rep (CSR) said was the same as the online instructions for troubleshooting an e294 error. Basically, remove the device from the app, then do a factory reset on the thermostat, then try again.  I asked if I needed the C wire.  He could only say, "you MAY" need to add a C wire, or add one of their power adapters, or call a PRO to install it. However, one thing the CSR said as he was half reading out loud from some resource, was that the basic NEST thermostat -- not the learning one -- needed more power than the learning NEST thermostat device. 

I also read somewhere online that the C wire is a common wire which offers a "return" path for the electricity which goes from the transformer to the thermostat through the R wire.  So I installed a C wire from my furnace to my thermostat. But it STILL didn't work when I tried to fire it up through the Home app on my phone.  It gave the same e294 error.  When I had added the thermostat to the app, I had indicated that there now was a "C" wire, in addition to the R, W, Y, and G wires. 

At that point I was ready to send the unit back as defective, but I tried one more time.  This last time when I tried again I did NOT tell the app that there was a C wire.  I just listed the R, W, Y and G wires, and pretended there was no C wire -- even though there was now -- AND THE NEST THERMOSTAT BEGAN TO WORK! And it has continued to work for the last three days.

SOLUTION: So basically, I had to add a C wire (even though no where did anything say for sure that that was what was needed), and then NOT TELL the Home SET-UP app that the C wire was there.  So I hope this helps someone else, and saves that person many frustrating hours!

And if Google Nest engineering reviews this post, I think they need to add better troubleshooting instructions for all of us consumers.  Since they know the exact model numbers of our Nest devices from the QR code which we scan with our phone-cameras, and they know what wires we have from the set-up app, I would think they should be able to add a routine in the set-up instructions for those of us who have basic Nest thermostats and who only have R, but not C wires, telling us how to set-up our devices like I had to discover after many hours of trial and error.

View Recommended Answer in original post

91 REPLIES 91

Ldrumheller
Community Member

My fix was VERY EASY. I reset everything and selected Rc instead of just R. Worked like a charm.  It should be smart enough to fix that issue on its own. 

I am very happy to hear that your experience was not a nightmare. Mine absolutely was. It seems once you receive that error message, there is no one fix to it. Each situation is as unique as a finger print, and but for the support from this community thread those who receive this error message may lose hope. I know I was ready to repackage the whole thing and return it. But since getting it to work, like you mentioned, it has worked like a charm. 

Jeran
Community Specialist
Community Specialist

Hey there everyone,

I'm just checking up on this thread, did you have any more questions or need any additional help? 

Thank you for helping out on this thread, everybody!

Best regards,
Jeran
 

Jeran
Community Specialist
Community Specialist

Hey there,

Did anyone have any more questions or need any additional help? 

Thank you,
Jeran
 

Steveintx
Community Member

Hi Jeran. Thanks for the offer. After you guys helped me figure out how to connect the c wire, things have been fine except... I've received a"low battery" warning twice. The first time, I tested the batteries and they were high, but I changed them anyway. The second time, I ignored the message and the warning eventually went away. Any clue as to what is happening?

grigrisa
Community Member

Same issue here; used 4 wires without the C and it was complaining about the red wire; reset and added the C wire and was complaining the C wire has no power; restarted again without select the C wire on setup and it works just fine.

My suspect is that the wiring is incorrect: there are 3 red wires in the setup selection: one is just R, and the other 2 have a letter (although it is not explained what those wires do). I think that if I switch from just R to one of the other 2 it will work even without the C wire, or maybe the C wire is just closing a circuit on the HVAC that let the thermostat to see the red wire... Can't say.

My old thermostat was using just the Y, G, R and W; so I guess it depends from the thermostat? But it works now so thanks for posting the issue and the solution.

BTW the fact that the setup ask you for the address, location and the thermostat has sensors is super creepy; I turned off everything but still this thing is a danger for my network and privacy; I may end up placing the thermostat on its own wifi network totally disconnected from home network

Ldrumheller
Community Member

I selected Rc instead of R (no common wire) and it resolved. So yes, your theory is correct 🙂 

Jeff
Community Specialist
Community Specialist

Hi all,

 

Several people are reporting having found fixes for the issue here. I just wanted to touch base and see if there were any others still looking for help. If you're needing more input, please let me know.

 

Thanks,

Jeff

Princesss
Community Specialist
Community Specialist

Hey folks,

 

We just want to check if you have seen our response posted above. Let us know if you have additional questions, otherwise we'll be locking the thread.
 

Best,

Princess

Princesss
Community Specialist
Community Specialist

Hi there,

 

Due to inactivity, I'll go ahead and lock this thread in 24 hours. Feel free to start a new thread if you need assistance with your Nest Thermostat and we'd be glad to assist you further.
 

Best,

Princess

Jake
Community Specialist
Community Specialist

Hey there,

 

I wanted to check in and see if you managed to see Mark's post. Please let me know if you have any questions from here. I would be happy to assist, and make sure you are good to go.

Best regards,
Jake

Jhonleanmel
Community Specialist
Community Specialist

Hi everyone,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,
Mel