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Nest Thermostat Error N260

madorio
Community Member

I installed my new Nest Thermostat and is showing Error N260 ... it seems that it is working, but why am I getting that message and how can I fix it?

 

1 Recommended Answer

So, I received the Nest Adapter kit but before I installed it I did some research at Google University. The Nest thermostat requires constant power to operate the display and such. If it doesn't have constant power, it relies on the 2-AA batteries to function. It will operate fine to control the heat, but some functions won't work. This is to conserve battery power. My thermostat wiring has 5 wires but only 4 were connected. (I have a forced gas furnace with an outdoor central A/C unit that operates through the furnace). I was able to use the 5th wire (black in this case) to use as the "common" wire. After turning off power to the furnace, I located the circuit board inside the furnace and found the harness that feeds my thermostat. Sure enough, the unused black wire was there. I connected that to the "C" (common) terminal on the circuit board and connected the other end to the "C" terminal in the Nest Thermostat. Bingo! The N260 message was gone and all functions are working as designed. I hope this helps some of you.

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39 REPLIES 39

David_K
Platinum Product Expert
Platinum Product Expert

Nobody likes error codes, so let me demystify it for you! That error code usually means your thermostat needs something called a common or C wire. I've linked a help centre article below that will help you troubleshoot this. Specifically, you should scroll down and refer to the "Your thermostat needs a C wire" section. Do let us know what happens when you try these steps? Try to be as detailed as possible so we know how best to advise.

https://support.google.com/googlenest/answer/9240096

David. I installed my Nest thermostat last July. I have gas forced air furnace with a central air unit. I have 5 wires. Red, green, yellow and white as well as a black which was never connected to my old thermostat. It is only in the last few weeks that I am getting the N260 error message. Any ideas?

I got an email this morning. Google is sending me, free of charge, the Nest Adapter. I will update here once I receive it.

I hope it works for you.  In my case this was a garage heater and that option didn’t work for my setup.  

So, I received the Nest Adapter kit but before I installed it I did some research at Google University. The Nest thermostat requires constant power to operate the display and such. If it doesn't have constant power, it relies on the 2-AA batteries to function. It will operate fine to control the heat, but some functions won't work. This is to conserve battery power. My thermostat wiring has 5 wires but only 4 were connected. (I have a forced gas furnace with an outdoor central A/C unit that operates through the furnace). I was able to use the 5th wire (black in this case) to use as the "common" wire. After turning off power to the furnace, I located the circuit board inside the furnace and found the harness that feeds my thermostat. Sure enough, the unused black wire was there. I connected that to the "C" (common) terminal on the circuit board and connected the other end to the "C" terminal in the Nest Thermostat. Bingo! The N260 message was gone and all functions are working as designed. I hope this helps some of you.

Ok i already had connected the black wire in c but it still gives me that error any idea

Is the black wire connected to the c wire terminal on the furnace control circuit board. Mine was not connected there originally. Once connected, check for power. Mine worked on the first try

Is the black wire also connected to the c wire terminal at the furnace control circuit board? Mine was not. Once both ends are connected, you should have constant power at the thermostat

JamesSun
Community Member

I dont know if there is anyone else facing the problem. But you need to connect the other end of the black wire in to the C terminal on the terminal block of the furnace well.

Yup, same exact thing so I just found black wire. Hooked it up and all set.

Did it work and if it did do you have a part number

I didn't end up using the adapter kit. I was able to add a common wire from my furnace control circuit board to the Nest Thermostat. The model# for the Nest Power Connector is GVNZ4

How were you able to get it for free

They sent me one for free, however, I didn’t need it in the end

I'd just like to use the battery w/o adding a c-wire.  It's a simple 2-wire set up (on or off for a radiant heat system).  Can I remove the error code or do I have to return them for a refund?

OK.  Once it drops wireless connectivity, the battery lasts forever without a c wire and the system appears to operate.  Unfortunately, the error messages continue to flash when using it.

Sears
Community Member

Did you get a solution to this? I’m in the same boat.

Sears
Community Member

I’m in the same boat. Did you get a solution?

Sears. See my previous post above.

Hey David, I recently just installed my new nest thermostat, its working great except it is showing the N260, the common wire issue. The only thing is, I have a C wire connected to the nest and to the furnace on the “C” terminal. I believe it may be a power issue with the common wire. I triple check connection on both sides and Im not sure what else to do.

Mine was working fine for months with three wires, then this error appeared. After reading the comments in this  thread that the unit requires constant power, I replaced the batteries. So far, no more error message. 🤞🏻

DougM
Community Member

so got the same error and it is power.  I am using the Nest E thermostat with a very simple garage heater.  The Google c wire solution didn’t work (the common is inside the unit, not accessible).  I have bought a transformer that connects to c, but I am unclear where to connect the second lead.  Right now I have a G wire, R wire, and W wire, all of which make sense for this setup.  So I add the new wire to C and ?????

thanks

happymac
Community Member

I had the same problem... I sent that transformer back and purchased https://www.supplyhouse.com/Venstar-ACC0436-Two-Wire-Kit. This worked perfectly.

Hi -- can you share how you attached the Venstar item to your furnace to make the Nest thermostat work properly?  Thanks in advance!

sandyscalzo
Community Member

I am getting n260 code. I admit during setup I had no idea what wire codes to use, so I chose two that works. The wires in my wall have no letters. But one is read and one is white. There is no third wire. 

We have the same situation. Did you figure anything out?

 

Bdurant
Community Member

Same error also.

Our downstairs thermostat has the green wire connected to G and works great. the upstairs has the green wire tucked away not connected. I'm connecting it to see if the error goes away 

DougM
Community Member

I did find a solution.  a 24 volt transformer, hard wired into the thermostat.

https://www.amazon.com/Adapter-Transformer-Requires-Honeywell-Thermostat/dp/B07C3J6PQX/ref=sr_1_3?cr...

eckwert
Community Member

Thanks. I'll look into it.

happymac
Community Member

N260 error? Need a common wire? If you have radiant (in-floor, baseboard, or radiator) heating, and you only have one red wire and one white wire at your current thermostat. You need to purchase a Venstar ACC04############-Wire Kit to connect up your Nest Thermostat. The cheapest place to find one of these is $28 at https://www.supplyhouse.com/Venstar-ACC0436-Two-Wire-Kit

Marc133
Community Member

This makes no sense. Why would I buy a thermostat where I need an ugly plug in transformer wired to it? Break out the wall behind it? Im returning mine. I have two learning thermostats on the same system with no C wire. Go figure.  Buy cheap get cheap. Pissed....

Marc133
Community Member

OK, here is a much better solution without ripping walls down or ugly black power connectors running up your wall. Google sells this and it installs on your zone valve to feed the power to the thermostat. Just bought one.  https://store.google.com/us/product/nest_power_connector?hl=en-US  And by the way, to my comment above the more expensive "Learning" Thermostats dont need the C wire. Same system. 

happymac
Community Member

The nest power connector that interfaces with the zone controller doesn't work with all boiler setups. Please check your individual system before purchasing. The Venstar ACC0436 two wire kit does work with all boiler setups and is easy to install.

Lita
Community Member

I am now also throwing the N260 code.  I already added the power connector and it appeared everything was working fine.  Now after a week or two I am getting this code.  Now what do I do?

a_shoja
Community Member

Ah! Running into this with Nest Thermostat just after a day. If I’d known earlier about the C wire issue and the need for an extra Nest Power Connector, I’d have gone with the Learning version, or given up on the upgrading idea altogether …

LoriAm
Community Member

Hi all ! Great conversation! I had Red to R, Black to G and White to Y, but was getting n260 notes. I also have yellow, orange and blue in my wall, but none of those were previously connected. Any advice or ideas on what to do with the extra wires? Thanks all! 

MarkP77
Community Member

Hey, just putting my 2 cents in. If you have to use the power connector and you hava a Taco relay box, connect the C wire to the COM terminal, it's usually located in the left top corner of the box. You will still get the N260 code until you do a power test on your thermostat in the settings menu.  You can Google the step by step details.  Hope this helps. 

Sjpunome
Community Member

I get N260 message constantly. 

 

I have a TACO board but don’t have a COM terminal. When I try to test my Nest by cranking the heat up to 90 (using the app), the power and valve open lights go on for a second or two then turn off.  

I am absolutely befuddled. I have the C wire from the adapter going in with the blue wire / furthest to the right terminal. That’s correct right? Or are the colors maybe all messed up. There aren’t letters on the terminals just 1,2,3,4. I’m in 4. 


thanks in advance for any advice. 

 

BillOCanada
Community Member

I cannot answer your question because I did not need to use the adapter. I found a common wire and connected that to the "c" wire at both ends.