Nest thermostat with e294 error, R wire not detected

[BruceB]

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?

[dm1170]

having the same issue. I only have two wires R and W.  I have reseated the red but still get the error.  

[OJMc]

Same issue here.  Only have two wires R and W.  E294 error despite reset.  Any solutions??

[BruceB · Accepted solution]

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.

[FractionalSloop]

Thanks Bruce!  It did what you suggested and now it works great!

[Sachin2876]

You're awesome Bruce, it worked !!!

Thanks for sharing the info. I spend almost 2 hours to get this Google nest thermostat to work but kept getting error E294 even when Red wire was well connected. After I read your post, I skipped C wire during the app setup and it worked. Issue E294 is resolved and thermostat started working. There is a bug in nest thermostat software app and they should rectify it.

[akonik]

Thank you Bruce and All others confirming it! It worked for me too. I was encouraged by all these confirmation replies. Otherwise I was about to give up and put the old annoying thermostat back in place.

[Rudeman]

It woeked for me too on google snow thermostat

thanks

Rudy

[Jhonleanmel]

Hi Rudeman,

I'm glad that this helped resolve your issue. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,
Mel

[Ltrickleson]

I don't have a c wire, but instructions said I didn't need one. Any solution?

[Markjosephp]

Hi Ltrickleson,

Thank you for taking the time in letting us know about your inquiry. I definitely wanted to stop by and see how I could help.

Are you getting the same wiring report? If so, please make sure that the wires are seated in the right terminals. If the issue persists, in this case, you must try to reset your Nest thermostat to default and add your thermostat back to the Google Home app.

Keep me posted on how it goes.

Best regards,

Mark

[guyellis]

This solved my problem as well.

[Nate1973]

Thank you! I did a factory reset without the C wire selected, even though it's connected, and it worked. I would have returned it without finding this!

Thanks! 

[Atul1]

How do you do a factory reset?

[SVTRocket]

Factory Reset Original Nest

1) Open menu by tapping at 2 o'clock position

2) Open Settings by navigating down to the Gear Icon

3) Open Settings and scroll down to Factory Reset

[BillP]

Bruce,

I had the same problem, and your fix worked.  However, I became concerned that, even though the C wire was connected, the Nest device was not using it, I.e. as if it did not exist.  We have no easy way to know without monitoring current flow.  So I lost confidence in the device and am returning it.

Note that using the device without the C wire can actually be bad for an HVAC system because of how it "steals" power to operate.

Bill P (Electrical Engineer)

[BillP]

One note of caution on this whole Nest fiasco is this:  If the Nest is "fooled" by indicating that you don't have a C wire when you actually do, is the device actually using it?  That could be a problem as the article below suggests.

https://smartthermostatguide.com/no-c-wire-install-a-nest-thermostat-at-your-own-risk/

One way to check whether it does use the C wire would be to temporarily lift it, insert an AC ammeter, and see if any current is being drawn when the Nest is running.  Obviously, a big pain.  This is the reason I decided not to use it even though I got it working.  No confidence in the device.

[kfontes]

Absolutely, what they are doing is disengaging that function to cover for the ID 10 T error for the Google genius that apparently can not figure out how to wire a Thermostat.  Funding > Competency.

 I have a 5 wire out the wall and a newer home and both units I am having problems with.

[hiett_431]

Solved the problem for me too on a boiler with former two wire system and added c wire.  Thanks Bruce!

Also, I went back into the thermostat setup after getting everything to work and you can 'modify wiring' , I added a c wire to the digital configuration and no new error. 

[drnickgarn]

Great catch!

[to_ash04]

Thank you Bruce.. this really saved me a ton of time.

[BrueberryMuffin]

Hello Bruce, had same error and was very frustrated and saw your post. I was about to either run an additional wire or used the fan wire "Y" (I. E keep the fan on automatic). But in my stubbornness I found an solution without using C wiring.  I hope this helps others. My wiring as follows: W, Y, G and R. No C connected. 

1. Reset Nest

2. Setup in  Nest for W, Y, G, R and C.

3. With setup near completion, Nest informs me that my setup is wrong.

4.  Rest Nest, but this time setup for my setup. W, Y, G, R.

5. Completed setup and no error message. It semmed to be working for 24 hrs so far. Will keep y'all updated.

6. Had a beer. 🙂 

[cornpops720]

Thanks, your post resolved my problem!

[Bill0405]

This worked for me. Cheers! 🍻

[UFGators]

This is pretty much what I did BM.  Thanks.  I told it there was a C wire, it then told me there was no W wire (huh?).  I then went back and changed it to say there was no C wire, and the **bleep** thing worked.  Crazy...

[CrimsonSparrow]

Yay! This resolved my error without having to add and bypass a C wire setting! I told it I had the C, then when it said I didn't, I just backed up and selected the 4 wires I did have.  Boom, it took it this time with no error! Hurray! 

[DFWMike]

Just bought my Nest (May) and still having same issue.  Google still hasn't resolved.  Thankfully your work-around was a lifesaver.  Thanks.

[Kricky333]

Thank you! Would've never thought to do that! 

[bfrederi]

Thanks BbM!  This installation was driving me nuts and trying your solution fixed the problem. To be honest, I'm not sure if it was adding/deleting the non-existent C wire (I have R, Y, W, G, and the old Honeywell had a jumper between R and Rc), or just performing the factory reset. But it got me past that infuriating E294 error. Not a fan of Google at the moment.

[BrueberryMuffin]

Lol... In this instance, it's the destination and not the journey they matters.;)

[Shakjsm]

Hey Brue, i am so glad it worked for now, i was frustrated, i dont drink so will have soda now.

[Jhonleanmel]

Hey there, 

@Shakjsm, awesome — glad to hear that your issue is fixed. It looks like we can consider this one complete, so I will lock the thread shortly unless I can help out with anything else. 

Best, 
Mel

[Westnew]

Bruce you are a life saver!  The installation guide says its easy to install.  That is very misleading.  Thank goodness I found your recommendation.  We had gotten very frustrated.  Resetting and wiring the c - wire but not declaring it  made it work fine for us.  Thank you, thank you!

[Honeybee73]

Oh my God! You are a lifesaver! This is exactly the problem we were just having. We followed your directions, and pow!, It works! Thank you so much 🥰

[coyotefam]

Bruce,

Omg, this fix works. Thanks

[Madmartigan]

Thank you Bruce.  This worked for me.   I find it strange that google via PSEG marketplace was offering "free" power adapters as this issue just magically started with me weeks ago. As expected, they are all out of supply, but they are available for $24.99. 

It took two tries but works.

Factory reset.

Check all wiring is clean. If you have a C wire, wire it up.

Remove device from home app.

Add device, scan QR code, follow next, next until it asks what wires you have.  Do not click C wire checkbox.  Finish all install, wifi, etc and test it.  Heat is on and no more errors.

[drnickgarn]

Bruce.... Dude... Thanks... I'd say a firmware update is needed, Google!

[jdwalsh97]

Bruce,

I lied on my diagram to Google, using the "already installed" and said I had Rc instead of R and Ta-Da beer earned.

[Awillma]

This worked for me. Very simple. No need to rewire. More time for beer!

[Kyser]

Thanks for the post, a hold year later. I just bought a google nest and had the same issue. connected the C wire (black) remove the thermostat from the app and reset the thermostat and it finally work.  Thanks again