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Can't get rid of N260 error code after installing Nest power connector

Community Member

I have a two wire heat only system with a 2020 Nest Thermostat. I got N260 code and figured out I needed the power connector which I ordered and installed. The low battery issues with losing Wifi etc have all gone away but the N260 error code will not clear. I tried fooling it by telling it I had a C wire but that just changed the error code from N260 to N261 because it detected that there was no C wire. It says the power test has not been run even though I have run the test multiple times. It seems like there a bugs I'm running into. Should I do a factory reset and start again with the power connector installed?

This is an older post from 6 months ago with exactly this issue that was never resolved.

Model: Thermostat-1.4

Device ID: ############4366521

Serial no.: 18161J3DB1PSF5

Software version: 1.1-9

Battery state: OK

Battery voltage: 2.83 volts

Control Board: Taco SR504


Community Member

Well I did the factory reset and now it's telling me I can't get through setup without replacing the batteries despite the batteries being declared full charged before I did the reset. So now I'm dead in the water.

What a piece of junk! I'm returning the thermostat and the power connector.

Let's see if anyone cares.

Community Specialist
Community Specialist

Hey jamescowdery, 


Sorry to hear about your experience with your Nest Thermostat and for the delayed response. 


During the setup, you may get a low battery message. This can happen if the batteries are loose or there’s a piece of the battery tab still stuck to the contacts. Kindly try the following suggestions:

  1. Pull the thermostat display off the base.
  2. Make sure you’ve completely removed the battery tab. Pull out the batteries from the back of the thermostat display and check that there aren’t any pieces of battery tab left.
  3. Put the batteries back in and make sure they are fully seated and facing the right way.
  4. Push the thermostat display back onto the base until it clicks into place.
  5. If the low battery message doesn’t go away, replace the batteries with high-quality 1.5 V AAA alkaline batteries from a known manufacturer.

You may also check on this link for more suggestions. 




Community Member

I am having the same issue as user above. Run the power test multiple times, have the nest power connector installed but the system won't detect it

Same issue. Power connector installed. Worked fine for a week, now losing wifi on daily basis, error codes n260. Seems to lose power when furnace is on. Had nest e at my old house, flawless. This has been the opposite experience, with a much much newer furnace. Troubleshooting is shallow and ineffective. Getting tired of having to setup the device twice a day to reset errors. 

SAME ISSUE.   Cannot get rid of N260 code even after installing power connector.  Everything seems to work but multiple attempts at power test fail.   Did a restart.  Did a reset.  Last time I added the 'c' wire in the app I got an M25 error code so removed that.   One time when I added it and went back it said  " c (power connector)" but cannot replicate that.   Can this system be run with the N260 code?  It evidently recognizes the power connector because until I added it the app would not let me proceed with the setup.    ????   

Hi.  I suggest you double-check your power connector connections and also verify that the power connector is wired properly.  I found that at least one of my connections was loose, causing a short, which caused the N260. After tightening all connections, and running a power test, the N260 disappeared and all has been well ever since.  Hope this helps.

Also, be sure to remove the jumper from the power connector, if your configuration requires it.

Thank you.   Wires are firmly inserted in the connector.  Im not sure what you refer to as jumper?   I only have two wires (red and white) and there is no control board.. they were coming from a plug in connector...  just wirenut to the thermostat wires.  

What happens if I continue using the thermostat with the code?   It appears to work fine right now

It's a little tricky to set up but once I got it working it works great, my issue was that it got disconnected from my Google account. 

Community Member

Same here. Installed the connector and successfully completed the setup. A few minutes later, I started getting this error. 🤷🏻‍♀️

Community Member

Also having same issue after installing the power connector 

Community Member

Come up with any solutions?


Same issue here.  Was getting errors, installed the power connector.  Everything works fine but I still get this stupid n260 error that won't go away

I gave up and went to a simple programmable thermostat. 

Community Member

An N260 suddenly appeared on my thermostat for no apparent reason.  After inspecting and tightening all connections (including those to the Nest power connector), determining batteries and external 24V power source were good, I ran a Power Test from the thermostat.  Power Connector was recognized and N260 error disappeared. Maybe N260 was caused by a bad connection causing a short.  Apparently the power connector isn't automatically recognized.  Anyway, all is good now.

Thank you again.  My stupid.   I now realize that even with the power connector I still need either a C wire or an external power source.  Duh.  (I'm a 75 year old non-electrician lady lol)  since there is no control board I will hopefully locate a C wire in the furnace or I will return the bloody device and reinstall my old programmable thermostat.   (I wonder if this is a common mistake made?)  Another opton is that I have an elec outlet on the other side of the wall in the bathroom and I could probably drill thru that wall and run a power cord directly to the thermostat. Thanks again everyone for your help!   

**RANT**  NO THANKS TO GOOGLE!  I chatted for hours explicitly detailing my situation, going through  the troubleshooting I already had done numerous times and sending multiple pictures of wiring in both the thermostat and furnace - which clearly showed no C wire or external power source - until they directed me to call a paid professional because 'something was wrong with my system'.  At that point I asked to have the case escalated and I was told my furnace was 'not grounded'.  Then I spent over an hour on the phone with a totally inept person trying to get the same case number escalated and was told I had to jump thru many of these same hoops before anyone would take my case so I obliged.  At the end I was told they could not help (I specifically told then to read the case notes and look at the pictures) and that I would have to call a Nest Pro to the tune of $129 for an initial consultation.  Being more frugal and stubborn than I am stupid I refuse to pay someone for such an easy fix.     

SHAME on Google.

KUDOS to my fellow contributors.   



Good luck to all future nest DIY installers!

If there is no C wire, you will need an external 24V power source (plugs into a standard wall outlet, available on amazon or ebay for about $15) which you would wire into the power connector (not at the thermostat).  This is exactly the configuration I have.  After you have wired the 24V power source into the power connector, do a power test so the thermostat recognizes the power connector.  This is exactly what I did to fix my problem with N260. My experience is that the power connector will not be automatically recognized.   Below is a link to the Nest Power Connector PRO Installation Guide.  Pay attention to the part that mentions the jumper removal when adding an external power source (page 10 - section 6D (Install the Nest Power Connector- If no C terminal is present in the HVAC system). 

Good Luck


Thank you Dwoodacre! You have been a big help!!  I appreciate your time..   Have a wonderful day

That is so much easier and safer than trying to find (if there is) a C wire in my furnace.   I've ordered the power source like you recommended. THANKS!!!!!

DWOODACRE....  I hooked up the transformer.   Removed the jumper in the power connector.   Installed the thermostat from the start and still cannot get it to recognize the C wire.  Rechecked all my connections several times and reran power test.   Unless the new power source is defective (I will check it on the morning)  I'm throwing in the hat and returning the thermostat.   Thank you again for your helpful suggestions.  

Community Member

Have you resolved this problem.   I'm having the same issue.   I did the factory reset multiple times but that didn't help..  are you running with the error code?   

You could try a factory reset, followed by a new install, followed by a power test.  That worked for me when I encountered my N260

Hi again..   did everything!  Tested power transformer. Updated. Restated.   Reinstalled.   Changed wiring.. both with and  without c wire.  When I add c wire it is not detected.   Rewired. Restripped and reconnected wires.  Everything is snug and in the right place.   Jumper removed.   When I run the power test it says done but status says "power test not run m25"  Any other ideas are welcome. Thank you! Again!!


Vin 31 lin 285w ps 285

All I can think of is:

1.  Be sure power connector is installed BETWEEN zone controller/valve and thermostat.

2.   Since power connector needs to be installed as mentioned above in #1,  be sure wires going TO thermostat and wires coming FROM zone controller/valve were not reversed when connecting to power connector.  The TO and FROM wires can't be reversed.

Beyond these two things and the process I used to correct my problem, I can't offer any other ideas for a two-wire heat-only system just like mine.

  • The HVAC wire  is connected to the thermostat with a wire nut.   I removed the wire nut and placed both wires together in the little clip with the appropriate power connector wire in the other slot in the same clip.    Sounds like you are saying I need to separate these wires (from HVAC and to thermostat)  and connect them to appropriate power connector wires (i.e. R or W) both sides of the power connector C wire?    I will try that tomorrow.  Thanks!   Oh.. the Nest app doesn't work with this... had to be installed on the Google Home app.   When I add the c wire in the app it allows me to but the thermostat shows it as not detected.

Also, be sure that the Nest app recognizes the wires attached to the Nest thermostat.

Community Member

Same issue here. My HVAC guy and I are losing our minds. This is costing me a bundle so I am mad. Nothing we do works.

Look at my replies to Fishingwishing for my knowledge on how to fix an N260 power connector problem.

Community Member

I keep getting the N260 error message I installed the power connector. I have a 3 wire heat only system. I am able to connect to wifi.

Hi.  First, check all of your connections to be sure they are correct and tight.  Next, try a factory reset, followed by a new install, followed by a power test.  That worked for me when I encountered my N260. My thermostats have worked flawlessly since I resolved my N260 last fall.   Good luck.  Dave.

Community Member

Tried all the above but still get error code N260

unable to run power test 

very frustrating 

Dismount the thermostat and temporarily remove the batteries.  Reinstall the batteries.  Then do a factory reset, followed by a power test.  That worked for me.  Also, did you remove the jumper in the power connector (if required for your setup)? If removing the jumper is required for you, do that first before you follow my instructions.