topic Re: Nest thermostat with e294 error, R wire not detected in Nest Thermostats

Nest thermostat with e294 error, R wire not detected

BruceB — Mon, 01 Nov 2021 14:00:59 GMT

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?

Re: Nest thermostat with e294 error, R wire not detected

dm1170 — Wed, 03 Nov 2021 17:15:01 GMT

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

Re: Nest thermostat with e294 error, R wire not detected

OJMc — Thu, 04 Nov 2021 00:34:10 GMT

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

Re: Nest thermostat with e294 error, R wire not detected

BruceB — Thu, 04 Nov 2021 19:24:26 GMT

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.

Re: Nest thermostat with e294 error, R wire not detected

FractionalSloop — Mon, 08 Nov 2021 18:47:40 GMT

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

Re: Nest thermostat with e294 error, R wire not detected

Sachin2876 — Sat, 13 Nov 2021 21:04:17 GMT

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.

Re: Nest thermostat with e294 error, R wire not detected

Rgrele — Tue, 16 Nov 2021 02:29:06 GMT

I tried not reporting the "C" wire during setup (although it IS connected). Still getting the same error. Google Nest: "E294: R wire is required".

Tried 4 times. Did complete resets. Double checked all connections.

Re-installed the old reliable Honeywell using the SAME 4 wires and that one works fine.

Disgusted!

Re: Nest thermostat with e294 error, R wire not detected

Rgrele — Fri, 19 Nov 2021 00:56:09 GMT

UPDATE: Upon further investigation, I ordered a 24V AC adapter from Amazon thinking that my wiring wasn't getting the correct voltage. Before I installed it into the system, I decided to try to hook up the Nest thermostat one more time. When I inserted the red wire into the hole, the tip of the wire broke off (perhaps it was defective?). So I stripped off some insulation and reinserted the red wire and performed the setup one last time. This time NO E294 error! And everything worked.

I'm assuming that there must have been something wrong with the red wire not making a good enough contact when inserted the previous times.

Now that it's working, I won't need the 24V AC adapter. My 10 year old Trane furnace evidently has enough power to make the Nest happy.

Re: Nest thermostat with e294 error, R wire not detected

Pinemartin — Tue, 23 Nov 2021 00:21:01 GMT

I had the problem, and was able to fix it by doing a factory reset. I just went through the same setup questions again while the unit was plugged in and the furnace powered. This time the setup worked perfectly with no errors. Seems weird but definitely worth trying!

Re: Nest thermostat with e294 error, R wire not detected

knowmoore — Wed, 24 Nov 2021 18:56:06 GMT

We had the exact same issue, and BruceB's solution works perfectly. Google would save a lot of money and time by simply updating the instructions. Don't check the "c" wire when it asks which wires are present!

Re: Nest thermostat with e294 error, R wire not detected

guyellis — Fri, 26 Nov 2021 23:31:01 GMT

This solved my problem as well.

Re: Nest thermostat with e294 error, R wire not detected

Nate1973 — Sat, 27 Nov 2021 20:12:40 GMT

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!

Re: Nest thermostat with e294 error, R wire not detected

BillP — Sun, 28 Nov 2021 18:28:02 GMT

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)

Re: Nest thermostat with e294 error, R wire not detected

hiett_431 — Sun, 28 Nov 2021 21:53:03 GMT

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.

Re: Nest thermostat with e294 error, R wire not detected

Bercpa2 — Mon, 29 Nov 2021 00:00:57 GMT

I tried all of the above fixes and several factory resets with no luck. I'll give them on their support was good today. Finally I factory reset again and there's a point where you can tell it that it's already installed. It asked me questions it hadn't asked before then FINALLY showed me a display showing which wire it did not find. It was the white one. It had never shown me that screen before. Hopefully it will help someone else!

Re: Nest thermostat with e294 error, R wire not detected

pengee — Wed, 01 Dec 2021 03:01:34 GMT

I had this same issue. What I noticed was that in the app you could see the wiring configuration and it had all the wires I had selected during setup, but they all said something next to them, I can't remember what, but it indicated they were missing or not connected. From this screen you could re-add wires and it worked for all of them, after which they showed their correct state, except for the R wire. You could not remove the R wire but it showed the option.

For the factory reset, I powered the furnace on and with the app, selected the alternate setup option where everything had been installed, rather than walking through the steps. This asked a somewhat different set of questions than the other setup path and at the end everything was working, no errors.

Re: Nest thermostat with e294 error, R wire not detected

bsmaven — Sun, 05 Dec 2021 18:13:55 GMT

Same messages showed no wires connected except my power connector. Tried removing red and white and my red copper broke off and is stuck in connector and can't get it out. Are these connectors bad? No thermostat should be this much trouble.

Re: Nest thermostat with e294 error, R wire not detected

JimR — Sun, 05 Dec 2021 19:19:39 GMT

I was getting the same repeated error telling me the red wire was needed even though it was fully connected. Reset and retried a few times. Then by chance I decided to designate the Rc terminal instead of the R terminal for the red wire in the home app. Started working immediately.

Re: Nest thermostat with e294 error, R wire not detected

to_ash04 — Sun, 05 Dec 2021 22:54:57 GMT

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

Re: Nest thermostat with e294 error, R wire not detected

Edsmith29 — Sun, 05 Dec 2021 22:56:29 GMT

I had the exact same problem. Deleting the device from google home, reinstalling it and changing to Rc designation for the red wire worked. Thanks so much!